“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. Please help my big pleco is on his side he is still breathing but not moving

    1. This commonly happens if they are over fed high protein foods and they’re primary a veggie variant of plecs and/or over feeding go a couple of days without feeding him at all and hopefully he’ll recover.

  2. We’ve taken on a neighbours pleco since he went into a care home but the tank he gave us had a leak during transit, we have purchased another tank as best as we could afford but the pleco keeps coming up to top of tank or banging himself on side. Is he ok?
    He’s about 12 years old, 12 inches long, now in a 94 litre tank and temp is around 24c

    1. sounds like he’s unhappy with his new environment make sure there’s places for him to hide a good size pot or a stack of wood for him to get in he should calm down over time. but 94 litres for a fish that size is a tad on the small side.

  3. Hi I have 100 litre boiob it come with a plec and 15 tropical fish is this ok ?

    1. Depends on the plec if its a common or one of the bigger species certainly not. if its one of the smaller species like bristle nose then sure.

  4. Hi, just done a clean on my tank and noq my pleq is upside down life less and looks like full of air?? Any advise pls. Thx Mike

    1. could be normal bloat but if it what i think it is its probably dead unfortunately previously I’ve seen this as a result of too high a protein died in a vegie plec

  5. Hi, we have 2 plecs, had them about 3 years. One is about 12 inches the other may be 9 inches. We have noticed that there are two strange looking green like mounds and the large plec seems to be guarding them and even laying on top of them. Any thoughts on this?

  6. Hi, I just found your site. It’s great. I’m really bothered about my rescue (now 12″) Common Plec. He’s in a 270l tank (he was in a smaller one when I recused him) I can’t get a bigger tank because of the weight on the floor (I’m in the UK … suspended floors in most rooms), my tank is on a concrete floor, but my partner says the base under the concrete may well sink! He built it 20 years ago so I guess he knows…I was looking at a 750l ish,(3/4 ton weight) but my partner says even 1/2 ton is too much to risk (550l ish). No one want’s my plec … I’ve tried ! He’s well enough but new reserch I’ve seen leads me to believe that fish think and feel a lot more than recently thought. Do you think he will display signs of anxiety like animals in a zoo ? Some time ago I put a plastic drain pipe in the tank for him to properly hide in, but he hasn’t once used it ! I have to make it as best I can for him. Is it good to have lots of bog wood (I’ve got some in his tank). I am just so worried that he eis suffering.

    On another note, I have, in another tank, a pair of bristtle nose plecs which have bred … 3 times in rapid sucsession !!! Many of the young were eaten, which I guess is natural. The adults are only about 2″ long but I supose not fully grown yet.I’ve read that there is no such thing as a dwaf bristle nose ! How big do you think they may get ?


    1. Lots of questions unless when he laid the concrete base he didn’t do it thick enough and cut corners it should handle the weight no problem. To put it in perspective I’m in a 1930’s ex-council house and there’s a 1500L tank the floor is fine.

      With regards to stress it should be pretty easy to tell, loss of colour is obvious one clamped fins overly aggressive behaviour etc.

      For your bn’s they get to 4-5 inch ish depending on exact sub species

  7. We have one male beautiful ornamental pleco and a couple of females, one his size. In the past a couple of lots of eggs but laid on bog wood so eaten by other fish. Put a shell in and it has doubled as a cave. The male broods and we isolated him rearing 35 babies which have been rehomed. Days after putting the shell back the process repeated. This time 135 babies. I think the shell will stay out this time!

  8. My Pleco has been on the front window for a few days now & I’m worried there might be something wrong with it

  9. Hi there
    I was so surprised to find that I have four baby plecos. Particularly since the two adult ones are completely different types!!
    I am a lazy fish keeper and carry out as little maintenance as I can get away with.
    Any tips for keeping my babies safe? Oh, and I don’t really want 6 plecos. At what stage can I risk catching them and moving them on?
    Many thanks

    1. While they may look different they may well be the same type especially if they’re ancistrus there’s lots of sub species that look quite different at first glance but are actually the same. Babies should fend for themselves pretty well if they’re big enough you can see them now nothing else you need to do wait until they’re 1.5″ – 2″ then it should be safe to move them on

  10. Hey my pleco is like fully black but right now part of his tail is white and part of his face is white what do I do

    1. Are you sure it’s not just his patterning? Is he stressed they do lose and change their patches when stressed. Is it like skin white or is it like a growth ontop of the skin?

  11. Hi
    Excellent article, thank you. We have always had pleco’s and one grew to abot 12inches and lived many years. At present we have three living very hsppily together. A larger female about four inches and a beautiful ornamental brisltlenose. We have had two lots of eggs in the past laid on bogwood and presumably eaten. At present the male is apparently lying on another batch in a shell fannjng the eggs and has been there for about four days. We have a spawning net and are wondering whether to put him and the shell in or wait for hatching?

    1. I’d leave them where they are until they hatch and male comes out. As soon as he’s out then move shell and babies to net

  12. I recently adopted a 14″ common plecostomus and have had a hard time finding info on amount to feed and if I could include other catfish in the 150 gallon tank I just got for him. Also is there any way to tell his age?

    1. At 14″ he’ll be able to devour about half a cucumber twice a week if your unsure just put 1/4 of one in a day weighted down remove after 24h and replace with another quarter after a week you should be able to judge how much he’s eating and adjust accordingly. His age could vary wildly no real accurate way to tell as far as I’m aware assuming he’s not been stunted by being in a small tank he’s probably at least 5-6 years old. My big one is about 26″ now and is 12 years old.
      In a 150 gallon tank you could probably have one more big plec or a few smaller ones I have 5 in my 1000l tank 2 commons and a couple of smaller ones

    1. Females don’t hold the eggs as such they drop them then leave its the male that sits and fans the eggs. The period of the females fertility/egg generation is quite short from what I’ve seen in the order of days

  13. Hi what dose it mean when your pleco put he/she fines up when swimming ?

    1. Doesn’t mean anything in particular though at least you know they don’t have clamp fin. Can also mean they’re settled in nicely as unhappy plecs tend to keep all their fins closed

  14. I would like to know when the sailfin pleco gets big how to secure the tank lid so it can’t jump out of my aquarium. Also are they aggressive towards to the owner being that big when siphoning it’s tank. I have a 55 gallon it’s only 2 inches long with no other fish in the tank since they get that big. Thx in advance. When it gets big will eat minos or or anything alive not dead.When is it necessary or how big before you feed fruits or/and vegetables. When they big will or can it break the aquarium glass. Much help needed.

    1. I just have glass condensation panels on my tank it stops them jumping out but netting would also work. they’re not really aggressive to people unless you try to stroke it mine is quite gentle and comes up for a belly rub. they won’t really eat live fish although I suspect they will have a good go at other smaller bottom feeders in particular i’ve noticed mine sits on top of and sucks on one of my loaches from time to time.
      fruit/veg can be fed immediately though try not to let it rot in the tank when they’re small just small disks of it are fine when they’re full grown they’ll finish off a full cucumber in about an hour.
      doubt they’d break the glass of the tank at 55 gallons it’ll have fairly thick glass anyway so will be fine.

  15. Hi I’ve got a 60liter tank and my common pleco is getting big he’s 10inch just wondering if it’s still okay for him to be in the tank

    1. God no! If it’s a 60 litre tank and he’s 10inches the he must be touching end to end if not bent double all the time.
      Give.him to someone with a tank more suitable or buy a bigger tank. For a common the smallest should really be setting like a 4*2*2

  16. I have a small pleco in my cold water fish tank with 2 gold fish. This morning he was lying on his side not attached to the glass and looks very pale in colour. He is still alive but doesn’t look right. Is there anything gets I can do for him? I did a water change yesterday but nothing different to what I normally do!

    1. Check the water temp while they are quite tolerant of lower temperatures especially with it being winter if the tank has got too cold (dropped below 19) he won’t be too happy at that they are after all tropical fish.
      Also is he getting enough food

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