Do Cory Catfish Eat Algae?

Excess algae growth in your freshwater aquarium can be unhealthy and unsightly. If you have an algae problem, and you’re considering adding a Cory Catfish to your tank, you might be wondering whether they eat algae or not.

As a general rule, Cory Catfish do not eat the algae that grows on aquarium walls, substrate, or decorations. However, as part of their diet, they can be fed sinking algae wafers at a rate of 1/6th a wafer per Cory Catfish per day.

Although Cory Catfish won’t eat algae, there are still plenty of other things you can feed your Cory Cat. There are also plenty of other ways to tame an aquarium algae problem. The rest of this article will discuss both of these topics in depth.

Corydoras | Source: Deposit Photos

What can Cory Catfish actually eat?

Despite their distaste for algae, Corys aren’t too picky about their food. They will happily eat many of the common food options found at your local pet store. You do need to make sure the food you’re giving your Corys will keep them healthy and well-fed though.

As Corys are bottom feeders, it’s important you give them food that will sink to the bottom of the tank. If you try to feed them food that floats near the top, there’s a good chance the health of your Corys will suffer due to them being underfed. This is especially true if you have other fish that prefer to eat their food near the surface.

Cory Catfish are also omnivorous, so you need to make sure the food you give them contains both plant particles and meat particles. You could accomplish this by feeding your Corys multiple types of food ‒ some meat-based and some plant-based ‒ but it’s easier and less expensive to buy food that contains both meat and plant elements.

Here are a few vetted options that will give your Cory community good health and consistently full bellies.

Corydora Catfish | Source: Deposit Photos

Bottom Feeder Pellets

One of the most common food choices for Corydoras Catfish are Bottom Feeder Shrimp Pellets. I recommend feeding your Corys API Bottom Feeder Shrimp Pellets, available on Amazon.

They are designed to be denser than the freshwater your Corys live in, so your Corys will be able to eat them when they sink to the bottom of the tank. They also contain shrimp, mussels, and seaweed ‒ so your Corys’ omnivorous needs will be satisfied by this brand of Bottom Feeder Pellet.

Tropical Sinking Wafers

Another excellent Corydoras Catfish feeding option are these Hikari Tropical Sinking Wafers, available on Amazon.

These wafers were developed specifically for Corydoras Catfish, and it shows in the ingredients list. Soybean and seaweed meal cover the plant side of your Corys’ omnivorous dietary requirements, while krill meal and silkworm pupae make up the meat side of the equation. Like the Bottom Feeder Pellets, they’re also designed to be denser than water, so your Corys will be free to scavenge the bottom of the tank for these tasty and nutritious wafers.

The downside to this option is that the price is a bit high for the amount of food you get. A 3.88 oz bag of wafers goes for $8.86 at the time of this writing, which is pretty costly by fish food standards. Therefore, I recommend using these as more of a treat than as a standard meal.

Two small spotted Cory catfish side by side | Source: Deposit Photos

Freeze Dried Bloodworms

If you want to add a bit more meat and protein into your Corys’ diet, freeze dried bloodworms are an excellent way to do that. Here are a few of the primary benefits of adding bloodworms to the diet of your Corydoras Catfish:

  • Bloodworms are particularly full of necessary vitamins and minerals.
  • Some fish find these tastier than regular fish food. If you have a Cory who is reluctant to eat, freeze dried bloodworms might spark its appetite.
  • Bloodworms contain a lot of protein, which is essential for keeping your fish healthy.

I recommend using the Omega ONE brand of freeze dried bloodworms, available on Amazon. Again, because Corys are omnivorous, you should probably use these as an occasional treat instead of a main source of nutrition.

Can Cory Catfish Eat Algae Wafers?

Generally speaking, algae wafers are a great food source for corydoras. Algae wafers are typically a mix of fish, shrimp, and krill meal plus wheat and several other plant ingredients. This makes them perfect for bottom feeding omnivores like cory catfish.

What kinds of fish will eat algae?

If you’ve got a particularly troublesome algae problem, Corys won’t be of much help. However, there are a number of other fish that will eat algae and help you to combat a bloom of the unsightly and potentially harmful substance. The following fish will get along with Corydoras Catfish, and can be kept in the same water quality and tank size as a Cory.

Bristlenose Pleco

The Bristlenose Pleco is an easygoing fish that gets along with almost everyone in a community tank ‒ including the Cory Catfish. Plecos are a “vacuum” fish, and will spend the majority of their day sucking up any algae that gets on your tank walls or aquarium decorations.

While their diet primarily consists of algae, though you may want to supplement it with bloodworms or wafers to make sure they get the proper nutrition.

Siamese Algae Eater

Siamese Algae Eaters are a calm, peaceful fish who get along perfectly with Cory Catfish. They enjoy algae so much that they were named for it, and adding a few of these to your aquarium will go a long way toward combating any algae issues you might be experiencing.

Like the Bristlenose Pleco, your Siamese Algae Eater cannot live on algae alone. You’ll also need to give it a fish food that is rich in both protein and plant matter.


Mollies are a particularly beautiful fish that fit in well with Corys. Although they like eating algae, they don’t do it obsessively like the Bristlenose Pleco and the Siamese Algae Eater do.

So if you’re in desperate need of a fish that will clean up your tank, you should choose something other than a Molly. But if you just want an attractive, docile fish that will chip in and eat a bit of algae, adding a few Mollies to your community tank is an excellent idea.

Otocinclus Catfish

The Otocinclus Catfish is a shy fish that can get pretty timid around most of its tankmates. Corys and Otos get along surprisingly well though, and you’ll often find them feeding and swimming in close proximity to each other despite the Otos’ wariness.

Oto Catfish will eat algae with the same vigor and enthusiasm as the Bristlenose Pleco and the Siamese Algae Eater. However, due to their smaller size, they will be significantly less helpful at combating algae than their larger algae-eating counterparts. Nevertheless, a diverse community of fish is almost always a good thing, so feel free to incorporate all of the aforementioned Cory-friendly algae eaters into your freshwater tank.

How else can I control algae growth?

If you’re dealing with a severe algae problem, buying some algae-eating fish isn’t going to fix the issue. To return your tank’s algae growth to a safe and attractive level, you’ll have to put in a bit of work yourself. Here are some of the most effective ways you can get rid of excess algae in your aquarium:

Feed your fish less

If you’re like most aquarium owners, you might be overfeeding your fish. This can contribute to your algae problem because uneaten fish food can increase the amount of phosphates in the water. Algae thrives on phosphates, so giving your fish more food than they can eat in a few minutes can directly lead to an increase in algae growth in your tank.

Make sure your tank isn’t in direct sunlight

Excess sunlight can also contribute to algae overgrowth. If your tank is located near a window, consider moving it to a more secluded location. If you’re using artificial light, consider reducing the brightness and intensity. You might also want to limit your tank’s light exposure to less than eight hours per day.

Add live plants to your tank

Plants and algae both need the same nutrients to survive in water. If you add live plants to your aquarium, less nutrients will be available to fuel unwelcome algae growth.

Clean your tank

If your algae problem gets particularly bad, you should consider cleaning the entire tank from top to bottom. The next time you change your tank’s water, take the following steps to remove all of the algae from your tank:

  • Scrape the algae off of the glass walls.
  • Scrubs rocks and decorations with a brush.
  • Vacuum your tank gravel.

Change some of your aquarium water weekly

Despite your best efforts, the nutrient levels in your water might still climb high enough for algae to flourish. The best way to combat this is to change ten to twenty percent of your water every week. This will cut down on the nutrients that fuel algae, which will in turn lessen the algae growth in your tank.