Do Corydoras Eat Algae?

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There’s a common misconception we need to obliterate in today’s article: the algae-eating Corydoras.

I will start in full force by stating that Corydoras do not consume algae. I’m not claiming this, I’m stating it because it’s a fact.

It’s also a fact that many inexperienced aquarists spread the idea of algae-eating corys due to the fish’s own misleading behavior.

Corydoras often seem to eat algae because they nibble at it occasionally. But they only do so as part of their food-searching behavior.

Corydoras nibble on a lot of things, many of which are not food, to begin with. If you gaze closely, you will notice that Corydoras don’t eat the algae but only nibble at them gently.

If they do happen to get some algae in their mouths, they will spit them right out.

What do Corydoras Eat?

So, if Corydoras don’t eat algae, what do they eat? These rank as scavenging fish that consume a variety of foods they can find on the substrate.

These catfish rank as opportunistic scavengers with an omnivorous diet that includes insects, insect larvae, detritus, microcrustaceans, food leftovers from other fish, and even fish waste.

Corydoras perform what’s known as sand sifting. They scan the substrate with their barbels and suck in sand occasionally when potential food is nearby.

They will then eliminate the sand through their gills and retain all sustenance left behind.

Can Corydoras Eat Algae Wafers?

Yes, they do, and they should. That’s because algae wafers don’t only contain algae, but a variety of other ingredients, depending on the product.

Many algae wafers contain spirulina, refined fish oils, krill, fish fillet, and a nutritional vitamin complex containing vitamins C, B3, B12, H, E, etc.

Algae wafers are actually important in the catfish’s diet, as they complement the fish’s diet quite nicely. They also sink and are easily digestible, making them great for juveniles and adults alike.

How much algae wafers your catfish should consume depends on the fish’s size and age but also on the rest of their diet.

They could use some occasional algae wafer treats and a good amount of veggies and animal protein.

How do Corydoras Clean the Tank?

Corydoras scan the substrate for food leftovers coming from mid and top dwellers. It may sound like disposable work since you can easily replace your catfish with a session of substrate vacuuming, right? Wrong.

Catfish are better cleaners than you could ever be due to their relentless and thorough search for food.

They not only find hidden food residues that could get lost in the environment but also consume them before they start to decay.

Your catfish’s activity is what essentially keeps the environment cleaner and healthier, eliminating the organic matter that could rot and produce ammonia in the water.

There’s a reason why Corydoras rank as some of the most essential fish species to have in a community tank. Especially in communities with a lot of fish that can produce an equal amount of mess.

What Fish Will Eat Algae?

Algae are generally harmless unless they grow beyond what they should. When that happens, algae can become an environmental hazard.

They consume oxygen, suffocate plants, consume valuable water nutrients, and even trap and suffocate fish. They also reduce the amount of light that reaches the tank’s lower layers.

You have a variety of control mechanisms in place to overcome this problem, but I prefer to let nature do the work. Algae eaters are my go-to strategy, and you should adopt it too.

Here are some good algae-eating fish to consider for your freshwater tank:

  • Bristlenose plecosPlecos are peaceful and resilient cleaners with a sweet tooth for algae and any other residual organic matter. These bottom dwellers are great as algae eaters and can adapt to a community setup better than most fish. Just make sure that there are no territorial or food-related tensions between the plecos and Corydoras.
  • Siamese algae eaters – This species provides you with some of the best cleaner fish in the aquarium trade. Siamese algae eaters are the most beloved for their appetite for algae and because they consume algae species that other algae eaters won’t. Black beard algae are the best example in this sense. They also eat microworms, detritus, and a lot of organic matter that ranks as waste.
  • Otocinclus catfish – These tiny, 1.5-inch cleaners are perfect for large and small community setups. They primarily consume brown and green algae and are constantly looking for feeding opportunities. They are also great for your Corydoras tank because they won’t necessarily stick to the substrate. Otocinclus catfish go wherever food is, mostly targeting the tank’s walls, various aquatic decorations and rocks, and any other hard surface that grows algae and detritus.
  • Snails – It may not sound right to mention snails on an Algae-Eating Fish list, but these animals are just too good to pass. Nerite, mystery, and Malaysian Trumpet snails are all perfect for the job. They’re not overly active but are great at algae control, especially thanks to their voracious appetite. Just make sure you go for larger specimens. Corydoras are known to target smaller snails that can easily suck from their shells.


Corydoras might not consume algae, but this doesn’t make them any less valuable for your community freshwater tank.

These catfish rank as excellent cleaner fish, removing most of the organic matter that could become an environmental hazard otherwise.

Get a few Corydoras for your tank and consider several algae eaters while you’re at it for the full package.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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