Plecos and cory catfish are two extremely popular catfish species in the aquarium hobby. 

These two fish have a lot of similarities, but at the same time couldn’t be more different. So, is it a wise idea to keep plecos and cory catfish in the same tank?

Cory catfish and plecos can live together as tank mates, because they are both peaceful fish. A tank size of minimum 20 gallons is needed. Certain species of pleco catfish need a bigger tank and will need a more plant-based diet, as opposed to cory catfish.

But before going further into detail, I think a general overview of both species is useful.

catfish (4)
Cory catfish
catfish (5)
Pleco catfish
Habitat
Amazon (South America)
Amazon (South America)
Diet
Carnivorous
Omnivore, depending on species
Temperament
Peaceful
Peaceful, males can be territorial
Tank
>20 gallons
>20 gallons
Size
1-3 inches
4-20 inches (depending on species)

Cory Catfish general overview

Photo by Jes

Cory catfish are peaceful, generally cheerful fish that just mind their own business. They don’t care about other fish, they just want to have their school. They’ll hang out around the bottom of the tank, digging and looking for food.

This is the thing which many people get wrong: cory catfish can’t be kept alone or in pairs. In fact, the minimum shoal size is 6 individuals, but the more the better. If they aren’t kept with friends of the same species, cory catfish will be stressed and feel uncomfortable.

In terms of general care, cory catfish are quite easy and hardy fish. Most specimens you’ll find are captive bred and they’re flexible in terms of water parameters. Some species like C. panda are more sensitive to water quality and die more easily. If your cory catfish keep dying, here’s my full guide.

Pleco catfish general overview

There are big differences between species of plecos. The most known are the bristlenose pleco and the common pleco, but there are dozens of other interesting species.

Most plecos species are omnivorous, but some are carnivorous (e.g. zebra pleco) and some herbivorous (e.g. the clown pleco)

This fish is known to be somewhat reclusive, spending most of their time in caves or hiding places. They will become more active during the night hours, but they’re not nocturnal.

Plecos are as opposed to cory catfish great parents. During the breeding process, the male will guard the eggs and fry in his breeding cave, until they’re ready to care for themselves.

Lastly, plecos are usually not aggressive. Males can fight or in extreme cases kill each other for dominance, but this can (in most cases) be avoided by having a large tank with lots of caves and hiding spots, as well as having more females than males.

An albino bristlenose pleco male. Photo by Thomas Siems

Small anekdote (The reason I say in most cases): I have had this happen to me once. I was sold a trio of the zebra pleco (1m:2f). They spent most of their time in the caves, and I didn’t want to disturb them too much. One day, I saw the big male sitting in another cave with a ‘female’.

Excited as I was, I thought they were spawning. Turned out, the male had killed another male and I found him dead the day after… Not only had I been scammed, but I lost an expensive fish because I didn’t notice. Ouwch… (I had plenty of caves/wood in the tank, btw).

If you want to know more about pleco aggression, read my full guide here.

Deciding factors for keeping plecos and cory catfish together.

Water parameters

Plecos and cory catfish both originate from the Amazon bassin. This means that mostly, they’re compatible in terms of water parameters. However (you here me coming), this depends on the species.

Considering most of you will have the bristlenose pleco and albino or peppered cories, you’ll be fine. Both species will do fine at a water temperature of 71-77°F (22-25°C)

Water temperature will be the biggest deciding factor, as almost all (pleco & cory) species do well in pH 6-7.5 and have similar preferences in terms of GH/KH.

Plecos tend to have a preference for higher water temperatures, while cory catfish can live in cooler water. Here are some cory catfish that can live in higher temperatures

Sterba’s cory catfish: 75-82°F (24-28°C)

Emerald cory catfish: 72-82°F (22-28°C)

Gold/Orange Laser cories: 72-82°F (22-28°C)

If you want to know the perfect water temperature for your fish, I’ve written two guides on this topic. They cover the temperature per species, and more.

The best water temperature for pleco catfish

The best water temperature for cory catfish

Diet

Cory catfish are mainly carnivorous fish. If you want to keep them together with cory catfish, you’ll need to feed a varied diet of both meat-based foods and plant-based foods such as vegetables and algae wafers for the plecos.

That is if you have omnivore or herbivore plecos like the bristlenose plecos.

If you keep your cory catfish together with a carnivorous plecos species, it’s obvious that they will need no plant-based foods. Only occasionally maybe to provide them with some extra nutrients.

Here are my favorite fish foods that can be fed to both species:

  • Repashy foods – All fish love Hikari! It’s a gel food you can easily make yourself, very high quality.
  • Hikari carnivore pellets – As in the name, suitable for the real meat-eating plecos and cory catfish.
  • Hikari sinking wafers – A more all-round food for both pleco and cory catfish.
  • Hikari Algae Wafers – Both cory catfish and pleco diets should be supplemented with a small portion of plant-based nutrients.

Tank size

Most pleco and cory catfish species need a 20 gallon tank. Plecos really thrive in bigger tanks, like 30 gallons.

As we discussed already, plecos can become aggressive in some circumstances. It depends on the temperament of the fish, too, but this behavior is almost always territorial. 

If your pleco feels it has too little space, and the cory catfish have no other option but always coming close (because the tank is too small) both fish will be stressed.

All of the numbers I use are relative. In almost all circumstances, you can keep more fish in a bigger tank. Because every tank is different, these are just baselines and the numbers I give differ in each case.

It’s important to ask yourself two questions:

  • How many cory catfish/ plecos do I have?

The more fish, the more chances on conflicts. Unless you have a 30 gallon + tank, I’d recommend to not keep more than 2 males. In a 20 gallon, you can have one pleco male (or multiple females, they tend to be more peaceful) and a group of approximately 10 cories.

You can have a bigger group of small cory catfish like pygmy cory catfish, and these will also inhabit the middle layer as one of the only Corydoras species.

If you want to know more about how many cory catfish to keep, I’ve written a full guide on this, for every tank size. You can find it here.

  • What other fish do I have?

Because both cory catfish and plecos mainly inhabit the bottom layer of the tank, you should not add too much bottom dwellers to the tank. This will create even more competition. 

Tank setup

Female bristlenose pleco grazing on the algae growing on the wood. Photo by bored-now

The second important point to touch on is how your tank is decorated. It’s no secret that plecos like to hide, which makes adding hiding places and plants extremely important.

If you add a lot of live plants and hiding places, your pleco will feel more comfortable and thus come out more. Stones and especially driftwood provide great natural cover for both plecos and cory catfish.

Adding a sand substrate is best, but a small grain gravel is good, too. Cory catfish prefer a substrate in which they can dig freely. Plecos don’t really have specific needs in this regard, although plecos will sometimes dig in gravel and sand.

Breeding

Keeping cory catfish and plecos together is one thing, but breeding them in the same tank is another story.

Breeding plecos with cory catfish as tank mates

Breeding plecos with cory catfish is perfectly possible. Since pleco males are great parents, their eggs are in no danger for possible cory catfish. Cory catfish are also not hunting fish, and they will leave the pleco babies alone.

Breeding cory catfish with plecos as tank mates

This is usually not a great combo. Cory catfish are the worst parents imaginable, and will scatter their eggs through the tank. Not only will they eat their own eggs, but plecos will find them a great snack, too.

During the breeding process, harder to breed cory catfish species require water changes and specific feeding programs to spawn. 

Cory catfish fry is also more vulnerable than pleco fry, so they will die more easily in the tank and plecos might eat a small cory catfish fry.

I usually recommend to set up a separated tank to breed cory catfish in. This will save yourself and the fish stress.

Alternative tank mates for pleco catfish

After this guide, you might have come to the conclusion that cory catfish aren’t for you. Here are three amazing alternatives to keep with your pleco!

Shrimp

Shrimp, especially neocaridina shrimp are one of the easiest and most colorful additions to any tank. They are great cleaners, and will usually not get eaten by pleco catfish. Shrimp will do great in smaller tanks, so they’re a perfect fit if you have a small setup / small plecos.

Kuhli loaches

Kuhli loaches are mysterious but certainly very cute looking bottom dwellers. They take up the place of cory catfish, and are mainly nocturnal. These fish are often sold in bad conditions, which is why they might die fast after you bought them. They’re also somewhat sensitive. However, it’s all worth it if you see a happy kuhli loach swimming through your tank.

Otocinclus

Photo by AJC1

The third fish is a sucker fish, which spends most of its time sitting on leaves and the aquarium glass. They are fun to look at, though and make great tank mates for plecos. 

Alternative tank mates for cory catfish

You have cory catfish, but the tank looks a bit empty? Well, because cory catfish are very flexible, the possibilities are just about endless!

Shrimp

Shrimp, especially neocaridina shrimp are one of the easiest and most colorful additions to any tank. They are great cleaners, and will usually not get eaten by pleco catfish. Shrimp will do great in smaller tanks, so they’re a perfect fit if you dwarf cory catfish.

Read our full article on keeping cory catfish and shrimp.

Snails

Golden Apple snail in a freshwater aquarium.

Snails maybe sound that sexy, but they’re a great addition to almost any tank.  Sometimes, cory catfish will eat small baby snails, which is positive for keeping the population stabile. Snails are also great cleaners.

Read our full article on whether cory catfish eat snails?

Betta fish

Betta fish are another great tank mate for small cory catfish, because they prefer a smaller tank with moderate to low flow. Most betta fish will not have conflicts with cory catfish, as they will inhabit other parts of the tank (upper-middle and bottom-layer).

Read our full article on cory catfish and betta fish as tank mates

Conclusion

Cory catfish and plecos make good tank mates, although it depends on the species you want to keep. There’s quite a difference per species, with both plecos and Corydoras.

The most important factors to look at are tank setup & size, water parameters and diet. Set up a tank that’s at least 20 gallons with lots of hiding places so that the pleco will less likely be territorial. 

A water temperature of 71-77°F is fine, although there are pleco species that demand higher temperatures. Read our full article regarding this matter for more.

Lastly, cory catfish are mainly carnivorous and pleco catfish are omnivorous. This means that you will need to supplement the diet with vegetables and algae wafers.

Breeding cory catfish in a tank with plecos is usually not a good idea. Their eggs will be eaten by the plecos. On the other hand, it’s totally possible to breed plecos with cory catfish in the tank as they will protect their eggs from the cory catfish. Pleco fry is also stronger than cory catfish fry.