“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. My plecs used to be visible through the day but not recently. Also my large male has changed colour and now has yellow/brown stripes. Is this normal and why are they hiding more than usual at this time of year? Please help.
    Also as a footnote I think I’ve lost one, either that or she is expert at hide and seek. Just changed a third of the water and cant find her anywhere. Checked the floor, the bin, no sign.?

    1. 1/3 of the water is quite a large change the colour change is possibly because they’re upset. Have you checked your water parameters and temperature recently to make sure there’s not something out of whack? Usually extra hidey plecs is a sign of being unhappy as is drastic colour changes. I’d double check the water first and then do smaller water changes more often.

  2. Hi I really enjoy your article on the pleco. I have a question that I hope you can answer. I have , what I believe after ready this, two suckermouth catfish. The one I’ve had for about 9yrs just passed away and it was about 15in long, pretty big guy, the other one I’ve had about a year and is about 10in long. Before my bigger one passed it would lay on my younger one and wriggle on top of it. So my question is were they mating because the younger one is now acting strange rearranging the tank and staying close to this makeshift cave I put in the tank. Thank you for listening and I hope to hear back from you.
    Concerned pleco momma

    1. They probably were commons at that size its unlikely you had one of the rarer large plec’s as typically they’re not stocked and special order so you’d have known exactly what you were getting. With regards to the behaviour it could well have been they were going through the motions of breeding but without a cave big enough for them to actually do it properly.If you think of their arrangement one on top of the other both facing the same direction and imagine a cave around them so the one on the bottom couldn’t escape the would be the female on the bottom and male on top.

      Having said that of course plec’s do have some odd behaviour at times and one of my littler ones always seems to ride on the back of the massive one in the tank and they don’t seem to bother each other doing it it just looks weird.
      The one you have left is probably feeling a little lonely if it recently lost its friend they can be social at times especially if they’ve grown up together or spent a long time together. Commons only seem to get really aggressive when its breeding time

    1. Im smaller tanks they can be territorial but its mostly to bottom feeders. If you’re finding mid/top feeders are dying off there its probably one of 2 things. Disease came in with the plec’s or more likely you don’t have adequate filtration for the increase in bio waste generated by the plec’s

  3. This was a fantastic read I rescued a plec from q bad tank friend didn’t have a clue going be honest wasn’t over happy but 4 weeks on in a community tank and happy water perimeters I have a great pleco with quite a personality but I have. 55 gallon tank with 30 small community fish thinking of adding a extra under gravel filter to help with waste? Sometimes u catch the pleco pairing with the corys which is cute any advice on filtration gratefully received currently use a fluvial u4 havr him a bubble Wand and two air stone for oxygen x

    1. With a common plec they make a lot of mess. Under gravel filter won’t help that much but make sure you vac the gravel often at least every 2 weeks keep it clean. A single U4 is no where near enough filtration for a 200 liter tank with a common in it though consider changing to a canister filter one of the big Fluvals or Eheim or such

  4. I have noticed I have 4 baby plec’s in my tank they are on top of my filter and moving about on my floating plants

  5. I’ve got a white fluffy substance (don’t have a clue what it is) on the wood in my tank. Would this be satisfactory for the Pleco to eat or not?

    1. It shouldn’t harm them its just a kind of mould/fungi I’ve had it before and it caused them no harm, it does look nasty though if you want take the wood out and give it a good scrub under the tap that’ll clean it up then just put it back in.

  6. I have a small, maybe 2 inch pleco & I’ve just noticed that his surface is breaking down, it almost looks like it’s rotting away.. All my other fish are completely fine, waters fine, tanks clean etc- anyone know what it could be?

    1. Sounds like some form of fungi or bacteria you could try some broad spectrum antibiotics or some methyl blue something like that

  7. hello can sum one help me plz can I put cucumber in my cold water tank for my plecs if so can I just put it straight in the tank if I put it to a rock for the plecs and will my other cold water fish be fine with the cucumber in there I be happy if sum one can help me cus I have had them for time and I don’t want to kill them by putting cucumber in there

    1. Cut it in half lengthwise so the middle is exposed use weights to stop it floating and it’ll be fine. The plecs and the cold water fish will eat it

  8. I have a large leopard pleco in a 200 litre tank who keeps running up and down the glass wearing his nose away. He has managed to get down to the pink now. Should I be worried? He seems fine in all other ways though.

    1. Sounds like he’s not settling make sure there’s plenty of hiding space for him caves nice and dark to get out if sight

  9. Hey, so I bought a bristle nose pleco a few days ago and I found it dead the next morning. So I exchanged him out for a “common” pleco (because our tank is a little on the coldside (70°f) so I thought a bigger fish might do better) and the day after I got him (today) he is sitting at the bottom of the tank, he’s still alive but I’m worried I’ll have another dead fish on my hands. My tank is 20 gal (I know it’s small but I plan on upgrading soon) and all of the water permameters are at safe leves, the water’s probably medium-hard tho. I only have three platies and two goldfish in the tank, all of whom are healthy, I’ve had the tank for about four months now. Any idea what’s wrong with my pleco?

    1. could just be tank shock of him settling in to the new tank. Make sure the tank water is tip top if unsure do lots of small water changes. Also try to soften it up the best way of doing this is usually sticking some wood in to the tank which is doubly useful as plecs like to chew on the wood too (even if things like commons/bn’s don’t really get any benefit from it)

        1. Actually I just looked up after changing some of the water and noticed he was back to eating off the side of a tank

  10. Hi Dave!

    I have a pleco that’s about a year old. We have a 55 gal tank and have some tetra, zebra and a could of angel fish. They all get along well. My issue is my pleco jumping. I know I need to keep the ammonia and the nitrates and nitrites very low so I’ve been changing my water every few days to regain control of all the levels. Now that my ammonia is pretty much non existent and my nitrates and nitrites are very low, I thought my fish would quit jumping. He hasn’t. Thankfully, we have a cover on the tank and he hits it about once every 15-20 min. Any suggestions?

    1. Some plecs just jump by big one does it occasionally scares the crap out of me I have no idea what causes it or if its even a tank issue that causes it or if its just natural behaviour not much help I’m afraid sorry perhaps another reader would like to comment

  11. My plec is loosin weight and doesn’t seem to be eating what can I do, I ave put cucumber mussels prawns nd algae wafer in but his belly seems to be Dippin in more nd more

    1. Well if its a common then prawns and muscles won’t help. If he’s not feeding on cucumbers and algae wafers though it sounds like he’s got some kind of disease putting him off his food perhaps an internal parasite though no real way to be sure

  12. All my fish died within a week ! Except one. My pleccy. Water was fine, checked everything twice. No visible illness. Some silent killer, any ideas ? Was thinking to reduce water temp and get goldfish ???

    1. If water levels are fine and it wasn’t an ammonia spike then chances are there was some form of disease in the tank. If you introduced new fish recently they could have brought it in probably bacterial. If you want to go with goldfish or any fish I’d probably dose the tank with a broadspectrum antibiotic before restocking. If you want to go with goldfish they are perfectly happy at tropical temperatures and like wise plecs are perfectly happy at lower temperatures although not completely cold water. Somewhere around 20 centigrade should be fine

  13. I did I found out he died and I checked his body and he had broken bones and stuff so I’m thinking the person at the store injured it badly with the net trying to get him out of the tank but my other 2 are doing great and are doing well with my Dino and angel fish.

  14. Hello I just got a common pleco and he was doing just fine when I got him in the bag but when I slowly got him in the tank and out of his bag he wiggled his tail a little and fell to the bottom. It’s been almost an hour and he looked like he’s paralyzed.

    1. More than likely simple tank sock. Did you drip acclimatise him or just throw him straight in? Was the bag water temperature massively different from your tank? They’re naturally quiet sensitive fish give him a few days let him hide don’t go chasing after him to get him out and he should calm down in a few days

  15. My plecos keep breeding, i have been informed that it is quite difficult?! 3 lots of babys in the matter of months.

    1. If they’re breeding that frequently and you’re not doing anything special then you don’t have common plec’s more than likely if picked up in an LFS then they’re bristlenose. You’d need a warmed muddy banked pond to breed common plecs.

  16. My yellow spotted pleco is acting I’ll ! I had to turn it back the right way up as it was upside down , I just done a 50% water change the heater was off for about an hour I thought it was dead but it’s breathing but hasn’t moved since ! Has this happened to anybody else???

    1. 50% is a big change all in one go especially if the heater was off and there was a major temperature change.
      He’s more than likely just been unsettled by the environment change let the tank temperature stabilize again and the water chemistry rebalance/him readjust to the change after such a large water change and he should get fine again. Perhaps give him 4-5 days to re-settle in again. Make sure the water is well oxygenated.

  17. i bought a 55 gallon tank already with 10 cichlids and two pleco one is black about 8″-9″ inches and one brown about 12″-13″ inches i was thinking that there was not enough room. so i bought a 110 gallon 48″x31″x18″ tank that i have the larg pleco in with two oscars. are you saying that that tank is also not big enough? and i only feed oscars what cold i feed the pleco that the oscars wont grab before it gets to the pleco? and last question what should my ph lvl be for this pleco?

    1. Depending on the plec types a 110 gallon (assuming yank gallons) could be more than big enough for your 2 or if its a tank buster plec it could be too small. Putting it in perspective I have a 7’x2.5’x2.5′ tank and the biggest plec now nearly goes front to back when layed out full stretch! however the smaller plecs are barely 6″ long so the tank is massive for them! it entirely depends.

      Assuming they’re the vegetarian type of plec feed them cucumber and algae pellets the oscars should leave that alone. The high protein food of the oscar wont do the plec’s that much good unless they’re carnivore plecs.

      Almost without exception plecs like neutral to slightly soft water it should be very similar in parameters to the oscars. Just watch for it swinging acidic as they won’t like that.
      They also prefer slightly soft/softer water where possible especially if you’re intending to breed them though going on the sizes they’re commons so unlikely to breed.

    1. He shouldn’t have algae on him? Alge grows on non moving things fish move. He may have picked up a little string algae though off a plant or something. That is fine he’ll come off on its own eventually you should never have to handle your fish

  18. I believe I have a Trinidad Pleco and is probably around 8 or 9 years old. My tank is a 60 gallon long tank. All of a sudden “Waldo” is floating upside down not attached to anything off and on during the day. He will swim away when I approach him. He acts normal. I have been using for all these years just one filter system but it is double filters. I put an aerator in the tank as well. Could oxygen be a problem all of a sudden, or is he getting close to his end of life. I am concerned about Waldo, he is family. Your thoughts?

    1. I’m not sure on the average lifespan of a trinidad plec never owned one 8-9 is a good age for most smaller plecs though. It may be he’s just having a problem with his swim bladder or perhaps a little protein bloat. Perhaps cut down on his food or make sure its the right food for his type. Good call in putting an airstone in it helps move the surface water more so the tank can do better oxygen exchange.
      May be worth while doing lots of small water changes for the next week see if that helps its possible the tank has swung out of balance a little.

      1. I haven’t changed his diet, so I would think his food is good. I hope it will correct itself. I will try the water changes as well.
        Thank you for your response!

        1. May not be something you’ve changed may be manufacturers have changed their recipe it happens from time to time

  19. Hi I have a pleco and never see it and if it does come to the front of the tank sees me and swims away well I have a bigger tank that as brought but the problem is it sticks to the net so how do I get it out

    1. I have one that you very rarely see its nothing really to worry about usually they hide a while they’re settling in (this can take a long ass time) it may be 12 months or more before they come out often. As for moving it they stick in the net due to their spikey fins getting them out can be difficult at times. Usually i find the best way is to just put the net + fish into the new tank turn the net upside down and eventually they free themselves. Some times if they’ve got both front fins wedged in so its splaying them open as the net unfolds you may have to get your hand in and just every so gently work one of the fins to be unstuck once that fin is unstuck and the fish can move forwards on its own it usually finds its own way out after that. Just be careful if you have to handle the fish, common plecs do have spikes and they will hurt like hell if they stab you with them.

      1. Ok thankyou as long as the net won’t hurt it Its big and have for I while first time moving to bigger tank Thankyou?

  20. There is nothing wrong with him its just that he’s not what I want in my tank that’s all and he is rather big

  21. My friends algae eater stays at the top of the tank but, drops his tail in a hooked position and has a white spot on his tail whats wrong with him

    1. By algae eater is it a plec or another type of veg eating fish? What type of plec.is it if it is a plec, what type of white spot is it? Lots of questions ideally need pictures too if you want any chance of id’ing what’s up with it

  22. If I wanted to donate a pleco were would I go I live in Portsmouth

    1. I think this comment requires a full post to address I’ll try and make a post about it tonight for you as its a common problem people with tank busters trying to rehome them

  23. My plec has become very aggressive towards my bigger fish such as my parrot fish.does anyone know why he’s turned nasty.???

    1. They usually get aggressive when there’s not enough space in the tank for them to stake out their own territory. Could be too many fish in tank. Could be tank is too small for it. Could also be he’s getting I to breeding mode and just needs a member of the opposite sex adding

    1. Yep as long as the water is warm enough to support the plec remember they are a tropical species so can’t live in cold water but will be fine in warm ish water so will the koi

      1. Great post. Thanks. Just introduced Marvin (on account of him always being starving) a baby pleco, to our tank with 2 angels and 3 clown loaches, and our three long serving (and remaining) 4 white cloud minnows and will follow your advice. Cheers. Paul

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