“Common” Pleco

Let me start by saying there is no such thing as the “Common” pleco. The word common is used as a coverall to describe many different types of the species.  Nearly all the fish covered by this catch all are mis-sold to hobby aquarium keepers who through lack of knowledge and awareness end up causing harm to the fish.

In my view fish retailers should make the prospective buyers more aware of the potential size the fish will grow to and refuse to sell even babies to anyone with a tank smaller than about 150 litres.  These can grow to be BIG fish.

Introduction to Plecos

Pleco is a name used for the catfishes of the family Loricariidae . One of the species in this family is named Hypostomus plecostomus and the name Pleco is derived from the name of this species. Today, the name Pleco is used not only for Hypostomus plecostomus but for all the members of the family Loricariidae . Plecos are also known as armored catfishes, since the longitudinal rows of scutes present on the upper part of the fish resembles old-fashion armor.

If you purchase a Common Pleco in a fish store it can be one of several species, including Suckermouth Catfish ( Hypostomus plecostomus ), Bristlenose Catfish ( Ancistrus dolichopterus ), Sailfin Catfish ( Liposarcus multiradiatus ) or Amazon sailfin catfish     ( Liposarcus pardalis ). The name Common Pleco is used for a lot of different brown-mottled Plecos that grow rather big in the aquarium. They all have similar habits and requirements, so this article is of interest even if you do not know exactly which species of pleco you keep.

The maximal lifespan of common plecos is not known, but it is believed to be around 20-30 years in captivity.

Pleco size

The fish sold under the name Common Pleco in fish stores is normally no bigger than 5-10 cm (2-4 inches) but this doesn’t mean that it will stay like that forever. Unfortunately, a lot of aquarists purchase fish without first finding out how big they can get as adults. In the case of the common pleco, you should expect your fish to eventually reach a size of 30-60 cm (1-2 feet).

Pleco habits

The common plecos are nocturnal creatures that are quite passive during the day. As long as the aquarium is lit, the pleco will use its specialized omega iris to keep the light from entering its eyes. When the lights are turned off in the evening, the omega iris will open and the fish will start searching for food.

Pleco temperament and suitable tank mates

common pleco

Unlike many other plecos, the species normally sold under the name Common pleco are territorial and keeping two or more large Common plecos together is rarely it good idea. It might work out fine, but you are definitely taking a risk and you should be prepared to evacuate promptly if they fail to tolerate each other. Different individuals have different temperaments and the temperament can also change gradually as the fish ages. The risk for violence is probably lower if you combine large common plecos from different species with each other, but more research is necessary before we can say anything for sure. An interesting exception is the Bristlenose catfish ( Ancistrus dolichopterus ), a lot of aquarists have managed to keep more than one Bristlenose catfish in the same aquarium (regardless of fish size).

A lot of different fish species can be housed together with Common pleco, but fat or flat bodied fish – such as goldfish and discus – should be avoided since plecos are found of sucking on such fishes.

Aquarium for common pleco

Aquarium size

Since the species sold under the name common pleco can become so big, the fishes will eventually need big aquariums. If you purchase common pleco for your small aquarium you must therefore be prepared to eventually get a bigger aquarium or find a new home for your common pleco. Large adult specimens normally need at least 200 – 375 litres (roughly 50 – 100 gallons) since they can reach a length of 30-60 cm (roughly 1-2 feet).

Use a lid!

It is important to cover the aquarium when keeping common pleco because they are capable jumpers. In the wild, plecos can use this ability to escape to better conditions during dry periods. They can not really travel on land, but they are strong enough to wiggle their way from a shallow puddle to deeper puddle in a drying riverbed. To a certain extent, they are capable of absorbing oxygen directly from the air so they will last longer on land than many other fish. If you come home and find your pleco seemingly unconscious on the floor, you should put it back in the aquarium because it might not be dead yet.

Do not let the water go all the way up to the lid, because the common pleco wants to be able to swim up to the surface and gulp air. The fish uses the air to control its buoyancy.

Aquarium decoration

Adult Common Pleco

When you set up an aquarium for the common pleco it is important to keep in mind that this fish eats plants. If you wish to use live plants, pick really sturdy and fast growing species and keep your fingers crossed. You can for instance try java moss, java fern och some sturdy crinum species. Also keep in mind that plecos are fond of uprooting plants. Use heavy stones to secure the area around each plant or go for floating plants and plants that can be anchored to aquarium decoration instead of planted in the substrate. Last but not least, keep your common pleco well fed at all times. A pleco that is given plenty of yummy vegetables in the aquarium is less likely to devour the plants.

Keeping common pleco in a barren aquarium is not a good idea since this fish likes to have a safe place where it can stay hidden and rest during the day. Live plants are however by no means mandatory in a pleco aquarium since there are many other forms of decorations that can be used to construct borders, create hiding spaces and make the fish feel at home. You can for instance use flower pots, stones, caves and artificial plants. You should also ALWAYS include driftwood in the aquarium setup since the common pleco needs to chew on wood to stay happy and healthy.

Water conditions in the aquarium

The common pleco hails from fast moving waters and will therefore appreciate powerful water currents and high oxygen levels in the aquarium. The water temperature should be kept in the 20-28 degrees C (68-82 degrees F) range and rapid changes in water temperature should be avoided. Healthy common plecos are however quite resilient and can survive in both cooler and warmer conditions, at least for a while. The common pleco needs soft water and the pH-value should be kept in the 6.0-7.5 range (acidic to slightly alkaline).

The common pleco produces quite a lot of waste. Regularly vacuum up the faeces and change 30-50% of the water each week. If you allow the water quality in the aquarium to drop, it can make the pleco think that the dry season has started and that its home is about to dry out. In order to save itself, it might try to escape by jumping out of the aquarium. A desperate pleco can bash itself against the aquarium lid until it sustains severe injury or even dies.

Food for common pleco

The common pleco is famous for its ability to keep the aquarium algae free, but you should always supplement the natural algae growth with additional food to make sure that your common pleco receives all necessary nutrients. The pleco is an omnivorous species, but meaty food should only make up a small part of its diet. For small plecos, uneaten scraps of the meaty food you serve other omnivores in the aquarium will often be enough. Large plecos can be given shrimps and fish fillets once in a while.

Since the common pleco feed on algae and plant matter in the wild, it will appreciate algae and plant based food in the aquarium. You can for instance use spirulina tablets or wafers as a base. Spirulina flakes float and might therefore be gulped down by faster fish in the aquarium before the pleco gets at chance to find them. Some plecos will however learn to quickly swim up to the surface during feeding time.

In addition to dry prepared foods, give your common pleco some fresh fruits and vegetables. You can for instance serve cucumber, zucchini, squash and similar vegetables. Lettuce and other leafy vegetables are also highly appreciated. There is no need to boil of blanch fruits and vegetables. A practical way of feeding common pleco is to get a vegetable holder for the aquarium or make one using a clothes-pin or similar.

Last but not least, an aquarium where you keep common pleco should always include driftwood since the fish needs wood to chew on. Wood is an importance source of fibre for common plecos.

Breeding common pleco

Sexing common pleco

Sexing the common pleco is really tricky, but in some species the males tend to be smaller than the females and develop bigger barbells. Some sources claim that the chin barbells are somewhat smoother in females. The Bristlenose Catfish is fairly easy to sex since the females do not develop any “horns”.

Breeding common pleco

15 inch Common Pleco

Breeding common pleco in captivity is hard and only a small number of aquarists have managed to successfully raise common pleco fry in their aquariums. As mentioned above, large adults can be highly territorial so at big aquarium (750 litres / 200 gallons or more) with plenty of suitable hiding spots is recommended if you want to try breeding common pleco. In the wild, the common pleco prefers to use caves along the river bank as spawning sites and such conditions are naturally quite hard to mimic in the aquarium. When common plecos are bred in captivity for the aquarium hobby, they are normally bred in ponds, not in aquariums.

One of the easier plecos to breed in captivity is the Bristlenose catfish ( Ancistrus dolichopterus ). This species does not need a cave along a river bed; it will happily breed in a normal stone cave or flowerpot in the aquarium. Make sure that you plecos are happy and healthy in the aquarium and keep them on a nutritious and varied diet. It is also important that you provide them with optimal conditions when it comes to water quality, water chemistry, and so on. If you are lucky, your couple will get into spawning mood and the male will attract the female to the cave. The female will deposit the eggs and the male will stay around after fertilization to care for the offspring. He will also chase away predators. After 4-8 days the eggs will hatch and the fry will be free swimming within another 4-6 days.

182 thoughts on ““Common” Pleco”

  1. Thank you so much for the great information! This is brill! I’ll definitely be back with more questions if needed! Thanks again!

  2. I have two leopard plecos – the larger one – about 24cm from tip to tip – has all of a sudden got ‘white abrasions’ over him and small ‘holes’ in his tail??? I’m really worried – we’ve had him for over a year – it’s looks like his ‘skin is being eaten’ if that makes any sense?? Can you help?? Thanks

    1. Sounds like perhaps whitespot or some other form of fungus. There’s certainly no harm in quarantining him keeping the water nice and clean/fresh and perhaps even treating him your LFS should be able to give you some meds suitable for him. I can’t really help identify whats up with him without some nice detailed pictures though unfortunately there’s so many diseases and other things that all look very similar you really have to get a good look at the fish to be sure.

      1. I thought whitespot but looked it up and it looks nothing like what he/she has :-/ now I’ve had 3 dead fish overnight 🙁 their guppies/mollies – the temp is fine but I’m getting a new filter today as all of a sudden my one I have is playing up!! – also I only just found out that my plecos need wood in their diet?? And fresh fruit an veg?? I’m getting some driftwood today an cucumber in the tank….but you think I should separate just the one pleco with the ‘spots’? Thanks

        1. If other fish are dying then you may as well leave the plec in the tank and just treat the entire tank.
          If your confident its not white spot then I’d go with a fungus seems more likely if its visible rather than a parasite. Get something to treat it and treat entire tank. Do a big water change before you do and make sure there’s plenty of surface movement to keep water oxygenated

      2. I am about to change my tank from tropical to cold (koi) it is a 240 ltr tank and I’m wondering if my (common pleco) could possibly make/take the transition from warm to cold temp? I’m very fond of him and I don’t want to give him away! Thanks!

        1. Luckily they’re pretty good at cooler temps. I wouldn’t let it go below 16-17c but I have one that is quite happy at that temperature. On the upside too koi are equally happy in warmer water too they seem to actually grow faster in the warmer temps. Just if your lowering the temp then do it slowly over time allow him to adjust. Don’t just dump him in cold that will kill him.

  3. Thank you all the other sites said 2 weeks to a month but if it never stops then that is that how long do you think i should boil it i also been sosking it

    1. If it fits in a pan i usually boil them for half hour ish make sure any nasties are dead then i stick in bucket of water and leave it outside for 2 weeks changing the water every couple of days. It minimises the tannins leak but never stops it

    1. It always will even after boiling it still seeps out boiling just minimises it. There’s no real way to stop it completely

    1. If it’s out of a river as long as its not a heavily polluted river just pour some boiling water over it all just to give it a quick clean. Give it a good blast with hose pipe then chuck it in tank

    1. If you’re talking about fresh bought driftwood you’re prepping ready to put in the tank then just wedge it in a pan 🙂 Alternatively if you don’t want to boil it you can just leave it outside in the rain for a week or 2.

  4. Well i cut it in half took seeds out and boilrd it for 2 mim to sofen is thar ok o i am putting alge waffers in to at night but my other pig fish are eating it

    1. Don’t need to take seeds out or boil cucumber. They’re soft enough already that’s probably why he’s not taking it. Just cut it in half and weight it down in tank so it sits on bottom and it’ll be fine.

  5. How long after i buy my pleco should he start eating i put cuccumber and squash and it doesent look like they touched it i tied it to a rock with rubber band

    1. It’ll take him a while to work out that its food so just put a fresh piece in every 24h for a week or 2 and he should get the idea. If he’s not taking to eating chunks of it try cutting just the ends off a cucumber and then cutting it in half length ways so its easier for him to get to the soft inside. Not all plecs will eat the skin of them it can be too hard for some of them.

  6. I’ve been trying but he isn’t responding :/ I feel a little heart beat but he is just stiff and floating… I think I’m too late…

    1. May well be but just get temperature up make sure tank is well oxygenated and water is clean best you can do now

  7. HELP i just bought a pleco from petco and put it in a tank with my goldfish. day one was fine and he wasnt acting weird. today is day two and he is floating on the top of the water. when i touch him he swims away but very weakly, and when i leave him alone he begins to swim towards the tank wall to suck then he just floats to the surface again. I am really worried for him 🙁 i live in oregon where it is very cold so maybe the water is too cold for him compared to petco? i dont know… we got him to clean up the tons of algae in the tank… i think he is dying though please help me

    1. Wow did you not think to check his requirements? Pleco’s are tropical fish they need warm water get it heated up to between 20 and 25 centigrade he’ll be much happier then. Also when did you last water change what is the condition of your tank water you probably have too much ammonia in there and the shock of going from petco water to your water could also be killing him too

      1. Petco told me I would be fine when I named the conditions of the tank to them…So I assumed so because they know fish better than me…well atleast I thought they did. Thanks.

        1. Petco like any other warehouse style pet shop are staffed mostly by minimum wage muppets just after a job very few of their staff actually know about the animals they sell properly. Check your water temperature get it up to the 20 centigrade region then both the goldfish and the pleco should be happy. Gold fish are traditionally cold water fish however they do perfectly fine at higher temperatures.

  8. I have a 300ltr tank witk different types of tetra & 1 pleco, s/he is brown in colour with very faint grey stripes. During the day he tends to hide under an artificial tree root & will come out at night when I turn off the brighter of thhe 2 lights. ? S/he is about 4-5″ now &I do expect him to grow, my husband Matt & I are looki for a larger tank due to movi hou &havi more space.
    When we first had him about 3mths ago, he was half the size he is now & was swimming abo more although never to the top of the tank. Now of an evening/night, Trevor (as my husband named him) generally moves about the bottom of the tank, or goes to the bogwood of which there is plenty for him, can this be normal? Or is there a problem? I didn’t know until reading your advice (which is great btw) that they will also eat veg like cucumber etc, do I just drop it into the tank for my pleco?

    Thanks in advance

    1. Behaviour sounds perfectly normal for plecs they are nocturnal so will come out more when lights are off.
      Without seeing a picture to id exactly what type it is brown with grey stripes is probably a panaque of some kind. I suspect probably a l190 royal which if it is would mean its a 2 foot fish fully grown luckily their growth slows down considerably as they get older. They primarily eat the film that grows on wood but happily eat veg too.
      When putting on veg make sure you weigh it down so it sinks to the bottom as they almost never take floating food. Also he may not eat it all at first after 24h take left overs out of tank and put fresh in eventually he’ll get the hang of it and eat it all skin too.
      If you could upload a picture somewhere and give me a link i should be able to id exact type for you as some plecs are actually carnivores so wont take veg

    1. In all honesty i have no clue. My large common does it to the yoyo loach its been with since it was a fry. They don’t seem to harm each other and they’ve been doing it for years with apparently no ill effects. I’d be interested in a real explanation too if you or anyone else ever find one

    1. Sounds like its just his thing if hes fine in all othrr aspects and hes eating well then dont bother about it

    1. Do you not have any caves or such for him they sometimes do that if they don’t have somewhere to hide

  9. Hi there, I recently purchased a pleco (it seems to be a bristlenose) and I’m very, very worried about him. when I first got him the tankhad a lot of algae and he cleaned it right up. but he suddenly is changing color often, hasn’t cleaned/eaten much for days to the point the tank is getting gross, and he isn’t very active. once in a blue moon he chases these little frogs I have in there around and sucks on them like crazy and since starting that is when he got like this so I don’t know of its some how connected as weird as that sounds!!? My gravel vac isn’t working properly so I have to go get a new one which means I haven’t vacuumed it in a little while and don’t know if that’s the issue? I had the water tested recently and it passed? Any idea what’s wrong or what to do? Even the wafers he isn’t interested in. some people act like it’s just afish and who cares but I do, I’d like to do anything to avoid him passing. I check on him all the time now scared he won’t be alive. Forgot to mention the first two days of this I found him sitting on his back thought he was dead and flipped him with the net but he is still alive?! Pleeease help!! I have pics if needed!

    1. Have you researched the frogs they may be toxic to him. He may also have a disease of types would really need to inspect him to decide for sure but research the frogs!

      1. No. I haven’t actually, I just assumed it was fine because I bought them at the same time from the same store (obviously!) So I just thought if they let me it was okay but I guess we should never assume so I’ll find out what they’re called exactly and look into it. it’s just weird he has been fine until now, I’m so worried about him 🙁 he is losing weight, not eating and the last two days his gills are moving fast (breathing fast) he was on the glass the other Day so I was trying to inspect him and noticed black stuff around his hole (anus??!!) That looks to be just under the surface slightly and there was some just in the inside of his lips?? I wish I could post pics in the comments to show you. I check on him CONSTANTLY because I’m so scared… his color changes DRASTICALLY and CONSTANTLY!? Please, I appreciate any help you can give!? Any suggestions of what it could be? Thank you again, I’m really wanting to save him, I can’t believe how long he has held on but it won’t be Much longer unfortunately..

        1. If you just upload pictures and give me some links to them I can look there. Try putting some cucumber in see if that encourages him to eat. It may be worth while treating the tank with a general anti bacterial and see if that helps at all.

  10. Please can you give me advise on my plecs and catfish in relation to living with other fish and tank size (apologies for a lengthy post)

    I was given a biorb 60l tank with about 20 assorted fish including tetras and mollies a few years ago. After an unfortunate ammonia strike a few years ago I started again and bought some more tetras and mollies, but also a couple of catfish to help with controlling the algae growth.

    My LFS told me that it would be ‘perfectly fine’ to have two plecs along with all my other fish in my particular tank as they assured me they would only grow to 4″ in length not the normal ones that grow to 12″+. I am now wondering if they just said this to get the sale – I did give them the exact capacity of my tank, the filter type and number of current fish before asking if I could/should be able to keep two plecs. Based on the advice given from them that they won’t grow big I bought them.

    They have for the past 18 months done fine. They and the catfish and other fish all live quite happily in the biorb. The plecs are between 3-4″ and catfish are 3″. I have recently decided that to get a rectangular fish tank instead of the round biorb as there isn’t as much ground surface and you can’t see into the biorb as well as the standard rectangular tanks.

    So for the past 3 weeks I have been cycling the new tank with no fish just the existing filter, live plant and gravel. I had the water tested at the LFS after that time and he said to move the little fish over first to check they can cope with the change in tank/water etc. Then if they survive and the ammonia, nitrates etc balance out then I can add the larger fish gradually.

    First question: I think I may have too many small fish as it is before I add the plecs & catfish and therefore adding the plecs and catfish will be too much. Based on the rough guide of 1″ of fish per gallon, I am already pushing the limits with 5 neons, 3 harlequin tetras, 2 red-eye tetras, then 1×2″ molly, and 4 tiny mollies. And a zebra snail (which came with the new tank). They all lived quite happily in the same capacity before. So is it ok to add the plecs & catfish?

    Second question: Do I need to keep both plecs and catfish or is that algae-eaters overkill? Should I only have bought one of either a catfish or plec? Now I have a zeba snail will that eat the algae and so I don’t need either catfish or plecs?

    third question: as all the fish, plecs and catfish all existed quite happily in the same capacity of old tank, can I assume they will be ok in the new tank. Or am I being really stupid thinking I can continue as before?

    The plecs have done a great job of ensuring there’s no algae in the tank and so I would like to keep one if possible. They both get on – no fighting at all. I have bogwood in the tank for them to eat and hide behind and seem quite happy. The LFS I bought the majority of the fish and the plecs from has recently gone out of business (well there’s a surprise), and I’ve found a much better one. They have said I can donate my plecs to them if they grow too big.

    I don’t know whether to give them to the LFS now before I get too attached to them and before the water quality suffers because of overstocking, or try to accommodate one or both and not have the catfish (which don’t seem to do much in my tank).

    I’m not sure what type they are, but they’re dark brown with yellow colouring, in a ‘animal print’ pattern – not spots or stripes. I’ve just looked at some pictures and it looks like a sailfin which will grow WAY too big for my tank – why do shops say they only grow to 4″?? Of course it may not be a sailfin – it definitely wasn’t called that on the label but I can’t remember the actual name.

    My two catfish are grey in colour, quite unremarkable in looks. But swim incredibly fast if their hiding place is disturbed.

    Any advice at all is greatly welcomed. I just want to do the right thing and give them all the best environment, even if that means I give the catfish & plecs back to the LFS.


    1. This comment almost demands a full post about it there’s some general fish keeping information in there as well as how to identify your fish and their requirements. I don’t know if others want to chip in too but I’ll make a proper post in the next day or so when I get chance

  11. Barbecued pleco sounds great! However, mine’s a bit small at 8″. I need to move him on as I have 18″ tank. Had Plucky for about 8 years from 2.5″ and he’s in good shape, but he hasn’t grown for years and I would prefer to see him let loose in a bigger tank. The pet shop has plenty at the moment so will have to try and advertise to a good home. Any idea what he’s worth? I guess he’s a suckermouth – brown mottled, sail fin, suckermouth, good barbels, straight spine. Got a slight white spot on his nose as he likes to exercise by swimming against the tank wall. He used to freak out big time with a water change or any disturbance, and thrash against the tank walls like he would knock himself out. When everything is normal he just does his routine of chilling, posing and hiding! Great character, and now will let me get him out by hand while I do water changes.

    So, my point is I’ve been doing these water changes because I’ve had months of algal bloom clouding the water – done partial/full water changes over a long period, which isn’t great as fish are sensitive to any changes so you have to preserve the conditions when you do a change. I’ve also got the light on timer at two four hour periods. (Apparently you can reduce this further). None of this has worked. I’ve tested the water and the phosphate level is off the scale and this is undoubtedly due to Plucky. I thought I was feeding him minimally at one pleco wafer every two days, but maybe that is still too much? I only had a few danios/tetras left with him so I put in a couple of goldfish and a few more plants, thinking this might suck up the excess food/phosphate. Also charged the filter pads up with phosphate buffer granuals.

    There still wasn’t any change so I went for the dreaded flocculant. Someone said that they don’t want to use stuff in the tank which might not be good for the fish, but I’m sure aquarium additives are tested, and I tell you 3 small doses later and a 25% water change every two days – and me and my fish can see each other. Result! Fish look fine, even happy, the water’s clear, more plants, less phosphate, No Algae!

    This is a temporary fix, but it’s to be hoped that improving the other conditions will make it more rigid. Sadly, I think the logical solution though is to move Plucky on. So difficult when they live such long lives, and seem to have a rapport with you. Better in the long run though for all concerned I think.

    I’ll try him with veg till he goes.

    1. Phosphates don’t really cause green water or algae its too much light and not enough filtration/plants usually. BTW buffer increases phosphate levels you need something like rowaphos to remove it.
      1 wafer every 2 days is no where near enough for a common plec either I put a good hand full in a night for mine I’ll do a feeding time video one day

  12. Hi – We have recently been given a pleco to permanently take care of. He is about 18 inches long (very big) and has been in a 10 gallon tank all of his life (for years now). We have transferred him into a bigger tank and he has been doing very well. He has been there now for almost 2 months. Today he is constantly moving – swimming – diving – going to the top for “air” – going back to the bottom – he just won’t settle down. He has never done this before, in his entire life. What is causing him to do this? The only thing about his tank that seems to be out of balance is that the water has a green cast, and after researching this, we discovered that is is algae. We have been doing water changes and adding fresh water, and we have not been putting his light on, but it is taking a very long time to see the algae in the water slowly dissipating. In his previous home, the algae apparently did not have enough light to grow. We transferred a little of the water from his 10-gallon tank with him into the larger tank to help him make the transfer from tank to tank, and within just a few days, the water had the green cast – the algae – growing in it. SO – my question – what is causing him to be so restless? We are feeding him primarily algae pellets (which was his diet before) – tank temperature is as you have stated – I’m just not sure what is up. Thanks for any advice.

    1. Nothing is up with him really this is pretty natural for plecs all mine do it especially the bigger ones they get water everywhere.

      Some people say it down to lack of oxygen in the water I fail to see this as being the case and they never provide any evidence to back this up.
      Others say it when the plec is having digestion problems but again lack of evidence.
      Mine tend to go nuts for a day or 2 then settle down don’t worry about it.

      Your green water is a different issue all together and won’t harm the fish in any way. Its actually a great subject for an article as again there’s loads of potions and lotions to combat green water when in reality the real solution is very simple and basic

      1. Thank you so much! I wonder if our pleco is just so happy to be in a bigger tank that he is finally swimming around? He has been alive for years in that 10 gallon and couldn’t even really turn around properly he is so big.

        I didn’t know plecos ate “people” food – we will start offering some to him. Are carrots okay?

        And the green water – from what I’ve read, the easiest solutions I saw were to 1) limit the light and the algae would naturally die (it isn’t algae that’s on the glass or plants that the pleco can eat, they are microscopic and filling up the tank water) – they even suggested covering the side of the tank that gets the most light with aluminum foil to block the natural light, as well as not turning on the tank light, until the water is clear. And 2) to do partial small water changes daily, adding fresh water, until the water clears. Very small – not your normal size water changes for your tank, just a nominal amount, until the tank clears. Of course there is something sold in the fish store to eliminate algae in your tank but I have been against using this as you never know if it can be harmful to the fish or live plants in your tank, but I have always figured that using natural methods would be better.

        Thanks again for the comments. As someone else mentioned – this was my mother’s fish and she is no longer in this area. She asks about her fish every time we talk.

        1. He’ll be very happy having space to swim will just have taken him a few weeks to settle down in new home.

          Carrots are a bit hard for common pleas though they’re god for panaque’s like the l190.
          Blanched peas with shells removed, cucumber, courgette, red peppers mine especially like.

          As for the green water limiting light is without a doubt the best solution and if you have a side of the tank that gets a lot of direct sun covering that side will help a lot either with tinfoil or paint or even just a stick on covering

      2. My pleco is sick, does this sound familiar to anyone? He is about 7 in. long and I’ve had him for atleast 6 months in a 35 gallon tank. I notice starting a cpl weeks ago that he was not moving much and not eating much. I decided to change the water and when I did I added all of the appropriate stuff and even had the water tested and it was fine. Now lately he has just been laying on his side, not attached to the wall and breathing heavily. He rarely eats, even though I provide food. There are currently no other fish in the tank for about 3 months. Any thoughts or advice would be helpful. Thanks.

  13. Last night I found our bristlenose catfish, Andy out of her tank. I do not know how long she had been out. When I picked her up to put her back in her tank she was still breathing but she was dry and her tail was stiff. Once back in the tank she went belly up a few times and each time I turned her back over. This morning she is still alive but breathing rapidly. Andy is not moving much and even let me pet her in the water. Usually Andy is very skittish and hides at the sight of anyone or any noise. She is sucking the side of the tank out in the open and has not moved from that spot for a few hours now. I have also noticed that the bottom half of her body has turned lighter in color almost to the point of being completely white. Her normal color is black and goldishbrown. What can I do to help her?

    1. Update: today Andy is not doing well. All of her fines are frailed at the end and she has lots of red under her skin. She is not moving around at all and breathing abnormally.

  14. We have a common pleco which is a unwanted fish we rescued, and hes about a 11inches long and we have just bought him a tank with the following features:
    960L/H Filtration (15w)
    300L Volume Capacity
    Dimensions: 1229(L) x 434(W) x 730mm / 48” x 17” x 29”.
    Do you think this is adequate for him/her? we also have two rescue Corys that we are going to put in with him as they have always lived with him too!!

    1. Unfortunately no and massively underfiltered. Because plecs are bottom feeders its best to get as large a floor area as you can height isn’t that vital but at effectively only 4foot x 2 foot there’s not alot of floor space. Really for commons you’re looking at a min of 6×2 on base area just for a single fish. Obviously that’s ideal conditions and most people can’t really use that much space. If he’s been used to smaller spaces before you could perhaps keep him in a tank that size I can’t say I’d recommend it but he could probably be happy there you may find his life span is seriously reduced though. Other thing to consider is large commons are very very messy fish you need to be turning over at least 2500l/h for a tank that size again in an ideal world 3000 would do. So filter wise you’re looking at something like a Fluval FX5 or one of the big Ehiem’s.

      If you’re dead set on keeping him in a tank that size then keep a close eye on him and your water quality regular maintenance and changes will help feed him lots of fresh veg. A couple of cory’s will be fine in the tank and perhaps a few surface/mid dither fish but really the common alone puts you massively close to your stock limit for a tank that size anyway.

      1. Thanks for the advice.. The pleco came in a much smaller tank when we took him/her on and knew that we needed to get something bigger…unfortunately we lack room for a bigger tank but we will up the filtration and won’t put anything more than the Cory’s in with him/her. I read above that 200 to 375 litres is ok for an adult pleco that’s why I assumed this 300 litre tank was Ok …he/she does use the sides of the tank too and often swims about… We will keep an eye on him/her and see if we need to rehome in the future. Thanks again!!

        1. It depends on the fish. Smaller pleco’s are fine in smaller tanks unfortunately commons are what commonly called a tank buster they live for 20+ years and grow to 2 foot in length and a good 6-8 inch wide. That’s half the size of your tank!

          1. Just to let you know we managed to get a 540 L tank and fit it in our house for the pleco,which he/she went in yesterday after we had cycled the tank to make it safe :0) I hope that will be alright for now and if not as I said we will rethink a larger tank and rehome if we need too..although I hope it doesn’t come to that!!

          2. 540l should be just fine for one common he’ll love the extra space my big one loves swimming from end to end of my big tank and looks amazing when he does

  15. Have a small 3 inch long pleco, which I have kept in a small tank (7 gallons) and he has stayed that size for a whole year now. The problem I face is that I recently bought a 70 gallon (225l) tank and need a catfish as a bottom feeder. My choice is moving my pleco into the tank and risk it growing to big and uprooting live plants or moving a group of small anchor (stone) catfish instead but I doubt they will clean the tank as efficiently as the pleco

    Ps. I do not really want to buy a new catfish.

    1. Couple of points, If it is a common pleco and you’re keeping it artifically small by keeping it in a small tank all you’re doing is guaranteeing the fish an early death. While the outside of the fish appears to stop growing its insides do not. Move your pleco to your bigger new tank asap. If you’ve not already done irreversible damage to him he should grow larger again though may never reach his full size and may now be stunted living a shorter life. I would strongly recommend you do not buy any more catfish but instead focus on providing a better environment to your current ones that includes having suitable sized tanks for the growth potential of the fish.

      1. Thank you for the feed back. I guess the people at the fish store were hiding the fact they they grow on the inside and just say they only growing to the size if the tank.

        I did a bit of research and I believe that the pleco is a Trinidad pleco for it has spots on the body and fins but on the the head has irregular, leopard, spots, which I believe it looks a lot like the Trinidad pleco. The problem is I do not want the pleco growing to big and uprooting delicate plants and moving boxwood.

        Ps. I have moved him in the big tank for the moment and he seems to be enjoying it, for he is very active and is cleaning a lot more than he used to. I have decided if he gets to big I will return him to the fish store. I already know the store excepts fish returns.

        1. Trinidad is just a different name for one of the many species that make up the “common” type of pleco. They’re all big fish 18-24 inch usually. Because he’s been kept in a small tank you will probably find it’ll take him a long time before he starts to grow again so you’ll probably have it for a fair few years yet. He won’t really move your wood but he may uproot plants if they’re not rooted properly though even my fully grown ones rarely dig my plants up in the big tank

  16. Hi my plec has a white cut looking appear under him. I haven’t had them long as I took on my uncle who past away fishs. Not sure if this is where he goes toliet. ? It wasn’t there before.
    Thank you

    1. Without seeing a picture its probably just a war wound from fighting with others in the tank or got himself caught on some tank decoration. Their vent holes are quite a way at the back of the body near the tail and doesn’t really look like a cut. On males it looks like a little sticky out lump on the females its like a lumpy hole.

      If this looks more like a cut keep an eye on it you may need to treat the tank with some anti bacterial medicine just to make sure it heals well but it should be fine they’re pretty sturdy fish.

  17. hi i have just bought my first tank which came with 1 pleco 5 kio carp and 20 gold fish.I have been doing some research as i thought that a pleco fish is tropical,although the man i bought i from had no heater in the tank, and kept it with the cold water fish , i wasn’t sure if that was correct ,and was given some advice to buy a heater ,so i bought a heater and set it at 24c,now all the carp are dead and a few of the gold fish.Should i rehome the pleco and have the goldfish with no heater,as i feel awful that the fish are dying due to my lack of experience an ill advice please help as i want,what is best for the fish,but i have got strangely attached to the pleco even though i have only had him 3 days.I would really appreciate any advice that you can offer thank you

    1. Pleco’s are tropical / warm water fish, Koi and goldfish are cold water fish so basically just room temperature/whatever it comes out of the tap at.

      Putting in a heater will have killed the cold water fish though some goldfish are perfectly happy at tropical temperatures. Likewise though the common pleco’s are pretty hardy and are perfectly happy at room temperatures/cold water temperatures (though during winter you may need a heater just to keep the water at about 17-20 range.

      Basically you’ve gone too hot probably too fast as well a more gradual increase in temperature would probably have been fine.

      For now I’d consider getting rid of the plec and sticking with just cold waters or get rid of all the cold waters and convert the tank to a full tropical tank

      1. Thank you so much Dave for your great advice,i don’t think i am experience enough to keep the pleco,so will look for a new home for him,and start with goldfish. And in time once i gain more knowledge perhaps i will try tropical.Thankyou once again Kirsty

  18. Found an Adonis pleco, would this be ok to keep with the red bellies? He’s 12 inches, tanks 200litre, going to be upgrading in near future.

    1. Adonis plecs are carnivores and very territorial. So if your existing fish are vegetarians or cant support a meat diet it wont be a good match. Also any other bottom feeders you have will be in trouble with a carnivore ppec in the tank. Choose carefully based on the needs of your current fish. Commons are vegetarian so you have options.

      200l is pushing it for a plec of that size but if your upgrading soon you should be ok for a while just remember with territorial fish smaller tanks make them even more aggressive.

      1. So Adonis and red bellied piranha would be a good mix, I the new tank they’d get along better.

        1. Yeah just make sure theres some wood making sone hiding spaces for the plec or some caves you dont want either the plec or pirhanna getting too aggressive with each other as the red bellies if they try to pick on the plec may well injure themselves

  19. I’m thinking of getting a large common plec for my pygo tank, pygo’s are around 7-8 inch, thinking of getting a 9 inch plec, good idea? Bad idea?

    1. As long as the tank is big enough to hold a potentially 23″ long fish I see no reason why not common plecs get on fine with most other fish

  20. I bought a Pleco, unsure which type, as was new to fish keeping in 1976. I called him Rambo. Everytime we moved he travelled in a bucket. He ended up in a 3` long 12″ wide 18″ high Aquarium (no wood tho, didnt know about that at the time?) He died this year at the grand old age of 37 yrs old. Howz that. Shame my other fish didnt live that long too!

    1. Nice to hear you managed to keep it alive for a long time. In all fairness I do describe ideal keeping conditions and while I don’t really support aiming for non ideal conditions I am aware that some people have been able to keep them for many many years without hitting them.
      I think as long as your dedicated with keeping your tank maintenance up, the tank isn’t too small and you feed them a good diet commons are fairly hardy fish and can survive quite well.

  21. We have just been given a Pleco he’s about 10″ long, we didn’t have a tank so were given one, it’s 2ft x 1ft, it is tropical got the heater, filter and air pump, is he going to be ok?

    1. Not really if its 10 inches its more than likely a common they grow up to about 2 foot themselves and a good 8 inch across.

      In a tank your size he’ll get stunted growth and die pretty quickly unfortunately he’ll also dirty the tank water pretty quicl so to keep him happy youll have to do daily water changes.

      I can only recommend you quickly rehome him into a bigger tank at yours or move him on. There are many plec species that remain smaller and are more suitable to a tank your size

    1. Depends on which plec and the size of the tank. For example you shouldn’t really have a common plec even as a single in a tank smaller than 4’x2’x2′ but if you have say a 6’x2’x2′ then you could quite happily have 2 or 3.
      However if all you have is bristlenose plecs then you can quite happily have 4-5 in a tank as small as 150 litres. So it depends alot

  22. If your plec gets too large, eat it! I ate many when I lived in the Peruvian Amazon region as did everyone there. It is easy to prepare. Make a horizontal slit on the underside just bask of the head, remove the small gut, and place the rest whole on the grill. The meat is white and very tasty. This is for real!

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