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Cory Catfish And Plecos: Can They Live Together?

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Cory catfish and plecos are common species in home aquariums. They are so popular that aquarists often choose to mix them together in the same tank.

But this immediately raises one question: can both live together in peace? And if not, which species should you choose?

Since I have faced these questions many times in the past, I decided to devote an entire article to this topic. Let’s dive right into it.

Can Cory Catfish Live With Plecos?

Yes, cory catfish and plecos can co-exist. But naturally, there are plenty of exceptions.

For instance, a 24-inch pleco is a threat to a 1-inch pygmy cory. Even with a peaceful temperament, the 24-inch pleco may confuse the pygmy cory for food.

Smaller plecos are just as problematic because factors such as high temperatures, crowded conditions, and insufficient food can compel them to act aggressively.

Cory catfish, on the other hand, are too timid to fight back against bullies and predators. They are more likely to go into hiding.

But this challenge only arises when you neglect your tank. Plecos and cory catfish can live peacefully with one another in a well-maintained aquarium.

Choose the pleco carefully. Avoid pleco types like the leopard frog pleco with aggressive tendencies.

Beginners should stick with tried and tested options like the Bristlenose pleco.

It is hardy enough to live in the same water a cory catfish enjoys while maintaining a peaceful and friendly temperament.

Here are some tips I suggest you follow if you want to keep these two species together:

  • Make sure your tank is at least 20 gallons.
  • Stick to a group of six cory catfish.
  • There is no need to choose more than one pleco, especially if it is a male.
  • Keep the temperature between 72° F and 76° F (22-26° C).
  • Scatter some hiding spots, including caves, plants, and rocks.
  • Stick to fine gravel or soft sand as a substrate.

Keep in mind that debris and toxins can become a problem, especially if your tank is already crowded or smaller than 20 gallons.

This is true for two main reasons. First, a group of six cory catfish is quite a lot. And secondly, the plecos are pretty messy. They produce a lot of waste.

That’s why regular water changes and aquarium maintenance are critical. Don’t trust these bottom dwellers to clean your tank. Vacuum the substrate regularly.

Should I Mix Plecos With Cory Catfish?

You can mix plecos with cory catfish. Plecos are primarily aggressive toward each other. They don’t mind sharing a tank with other species.

They are an interesting addition to a cory catfish tank, especially if you suffer from algae overgrowth or an abundance of debris on your substrate.

A single pleco in a cory catfish aquarium will behave. You should only introduce a second pleco for breeding purposes. Take the second pleco out once mating ends.

This video illustrates how cory catfish and plecos can share the same tank.

Cory Catfish vs. Plecos: Which One To Choose?

Not everyone wishes to raise both cory catfish and plecos. There are aquarists who only want to choose one species, but just don’t know which one to choose.

Choosing between cory catfish and plecos sounds like a daunting task, but you can simplify it by considering the attributes each fish brings to the table:

1. Cory Catfish Are Usually Smaller

The fish size matters because it influences the aquarium size. Larger fish are challenging because they require a bigger tank to prevent overcrowding.

This is especially true for shoaling fish that can’t survive without tank mates of their own kind. Cory catfish are beneficial in this regard.

They can live in a 10-gallon tank because the creatures can only grow to a size of four inches, with the average being 2.5 inches.

Some cory catfish are even smaller than that. Take pygmy cory as an example. It has an average length of one inch. Albino corydoras, on the other hand, won’t exceed 2.75 inches.[1]

Smaller fish are appealing because you can keep more of their kind in a smaller, cheaper aquarium without crowding their aquatic environment. 

Plecos are not as beneficial in this area because of their size. 

Common plecos can easily grow to 24 inches in an aquarium, dwarfing the average cory catfish significantly.[2] Granted, this is not true for every pleco.

For instance, the gold spot dwarf pleco is just two inches long. If you’re lucky, you may also land a 6-inch Bristlenose pleco. 

But you’re also just as likely to buy a 24-inch Pterygoplichthys pardalis, which requires 100 gallons. 

If you don’t have the space or the money for a 100-gallon tank, you should steer clear of this species.

A group of Bronze corydoras, looking for food at the bottom of the tank.

2. Cory Catfish Are More Peaceful Than Plecos

Cory catfish are too peaceful to present a threat to their tankmates. 

The best they can offer in terms of defense is the sharp spines on their fins, which is why handling them with bare hands is so dangerous. 

An article in the Journal of Marine Biology and Oceanography has highlighted their ability to generate poisonous mucus through the gills.[3] 

But that weapon is a double-edged sword that incites enough stress to kill the cory catfish. In other words, cory catfish have no choice but to behave. 

They can’t fight back against predators, hence their desire to exist in groups of six or more. Fortunately, they are small enough to live in large groups without overcrowding the tank.

Their peaceful temperament makes cory catfish a perfect tankmate for various species, including guppies, neon tetras, snails, shrimp, loaches, etc.

They will thrive in a community tank. Plecos are an entirely different matter. First of all, keeping multiple plecos in the same tank is a challenge because of their size. 

Secondly, even though they have a relatively peaceful temperament, plecos become highly territorial when they mature. They can’t live with other plecos.

You can only maintain peace by keeping one pleco per tank.[4] But again, one pleco can live peacefully with fish from other species.

3. Plecos Are Excellent Algae Eaters

Cory catfish are scavengers that dig into the substrate in search of small insects, leftovers, detritus, and the like. It wouldn’t be an exaggeration to call them tank cleaners. 

However, even though they can tolerate algae wafers, cory catfish are not algae eaters. This is where plecos shine

A study in the proceedings of the Royal Society B (Cornell University) looked at the impact of plecos on a Chiapas river in Mexico.[5]

The study blamed the fish for restricting algae growth by absorbing phosphorous (a key component in algae growth) in large quantities. 

Texas A&M and Texas State Universities researchers also identified plecos as effective tank cleaners that grew rapidly and consumed algae quickly enough to prevent the organism from overwhelming aquariums.[6]

Plecos are more aggressive than cory catfish, and you shouldn’t keep more than one in a tank.

So What Is The Verdict?

Are plecos better than cory catfish? Not necessarily. If you could only choose one species, cory catfish would be the superior option.

Plecos have their advantages. The creatures are hardy enough to survive for 20 hours outside water.[7] They can even tolerate living in cold water ponds.

A paper in the Aquatic Nuisance Species Research Program praised these creatures for their boney armor, vascularized stomach (that functions as a lung), and tolerance for extreme conditions.[8]

However, for all their benefits, the plecos are too large. Because of their territorial tendencies, you can only keep one of their kind in an aquarium. 

More importantly, the plecos are too messy. They generate too much waste, canceling out their algae-eating habits.

You can’t call them tank cleaners because they produce as much waste as they remove. 

You can’t even trust them to keep algae out of the aquarium because some plecos lose their appetite for algae as they age.[9]

All in all, cory catfish are less of a hassle. Admittedly, they are not as hardy as plecos. 

But the creatures are decent tank cleaners that tolerate their own kind as well as fish from different species. 

You can keep large groups of cory catfish without destroying the tank’s chemical balance. If you can only buy one, cory catfish are the rational choice.

Male and female bronze cory catfish (the male is usually smaller).

Conclusions

Although they are both bottom dwellers and scavengers, cory catfish and plecos can co-exist peacefully in the same tank.

Ideally, you should pick a group of six corydoras and one pleco, preferably in a tank of at least 20 gallons.

But if you have to choose between the two, I would suggest getting the cory catfish. They are much easier to grow and get along perfectly with many other species.

References

  1. https://www.aquariumcoop.com/blogs/aquarium/top-10-cory-catfish
  2. https://aquanswers.com/small-pleco-species/
  3. https://www.scitechnol.com/peer-review/the-reversal-of-selfpoisoning-in-bronze-and-albino-corydoras-qZN9.php?article_id=11302
  4. https://animals.mom.com/can-multiple-plecostomus-put-same-tank-11126.html
  5. https://news.cornell.edu/stories/2013/08/freeing-pet-catfish-can-devastate-ecosystems
  6. https://www.smithsonianmag.com/smart-news/four-hundred-invasive-fish-dumped-from-aquariums-found-in-texas-river-180979485/
  7. https://blog.nature.org/science/2021/08/02/this-catfish-doesnt-just-move-on-land-it-reffles/
  8. https://www.researchgate.net/publication/306886343_Ecological_Impacts_of_Suckermouth_Catfishes_Loricariidae_in_North_America_A_Conceptual_Model
  9. https://www.unclebills.com/pets-and-pet-supplies/aquatics/aquatics-blog/aqua-blog/2017/11/14/plecostomus-benefits!