Skip to main content

4 best freshwater catfish that can help keep your aquarium clean

Catfish are special — they’re not just a fun and interesting pet but also a cleaner! Adding a freshwater catfish to your tank can help keep your little ecosystem in balance. Unlike most of the fish in your aquarium, catfish are bottom-feeders, which means they eat what falls to the tank floor. This can help remove excess food and algae from your fish home, which will keep your tank cleaner. It’s a no-brainer to bring one into your tank. Here are the best types of aquarium catfish to buy.

Two cory catfish in an aquarium
Dimitris Leonidas/Shutterstock

Cory catfish

A school of corydoras will surely liven up your tank. With over 160 species in this group, there’s a lot to choose from when you’re getting ready to select a type. While size, diet, and temperament vary a bit in this crew, cory catfish are nearly always placid and easygoing creatures. One key aspect of the cory: They need friends. No corydora will be happy alone in your tank, and for that reason, we don’t recommend these for a tank under 20 gallons. Depending on your existing environment, check out the pygmy, the peppered, or the elusive orange laser. Stock up on worms and, of course, catfish food before bringing your group home.

Synodontis catfish

This African fish will need a larger tank than your average cory. These guys are known for two unique characteristics: swimming upside down and “squeaking.” If you add a synodontis to your tank, you might hear the strange noise they make that actually comes from their bones. Also unlike the cory cat, many synodontises prefer the quiet life and will do just fine on their own. Be careful when selecting his tank mates, though, as smaller fish may look like a meal to a big, hungry catfish. You’ll have a number of species to choose from here, too, so look thoroughly at different kinds before making your final selection.

A catfish swims by a stick
Máté Molnár/

Otocinclus catfish

Running out of space? These catfish make a great addition to a slightly smaller aquarium and can live happily in 10 gallons, provided it’s not overcrowded with other schools. You’ll love putting these little ones in your tank because they’re voracious algae eaters who will gladly help with the tidying up. In fact, they eat so much, you’ll probably need to prepare extra algae for them if it gets low. Oddly enough considering their big stomachs, this is one of the smallest types of catfish that we keep as pets, reaching only about 2 inches as adults. A bit shy by nature, otos may hide in a plant or ornament, so fill your aquarium with places for them to retreat to.

Plecostomus catfish

Before you pick up a common pleco, don’t forget: These guys get big. You’ll need a 200-gallon tank or more to fit this fish, which can reach 24 inches in the wild (and about 16 inches in your home). Putting together a larger tank can present a fun project since it opens the door to new decoration ideas. This bottom sucker likes rocks and driftwood, so you’ll have to design your tank layout to incorporate both. Plecos also eat some algae with other plants and even veggies like cucumbers mixed in. If a pleco sounds like a good choice but you don’t have enough room, check out the golden-nugget or bristlenose varieties, which are a bit smaller. Depending on the kind you select, you may also need to provide meat like worms or substitute with catfish food from the pet store.

While these cool creatures do help maintain a fresh environment, they don’t eliminate the need for a filter. In fact, many catfish require moving water to replicate the currents they often live in. Watch carefully, too, for other fish gobbling up all the food before it gets to the bottom — some of the more timid kinds can go hungry when their tank mates decide to take their meal. As with any fish colony, not all types get along, so check with your vet or pet shop owner before mixing and matching. Once your freshwater catfish has settled in, he’ll add a unique look and diet to your aquarium and do his part to keep your tank squeaky clean.

Editors' Recommendations

Rebekkah Adams
Rebekkah’s been a writer and editor for more than 10 years, both in print and digital. In addition to writing about pets…
Looking to add corydoras to your aquarium? Here’s what you need to know first
Read this before bringing home a cory catfish to add to your tank
Two cory catfish hang out on the bottom of the tank

One thing you might not know about aquariums until you get one: Every tank needs a janitor, which may wind up just being you. When you first dive into this hobby, it can take a while to realize how much maintenance is really involved — don't think that the filter will do all the work. But if you want a little a help in that department, you can add a catfish to the fray. If you don't have a ton of experience with these bottom feeders, we recommend one of the corydoras since they're generally best for beginners.

What are corydoras?
This is a type of catfish, but there are actually more than 170 species to choose from. These are a well-known group of swimmers who get their name from their barbels, which look a bit like whiskers. While you'll find dozens of options in the pet store, you will likely narrow it down quickly based on the size of your tank, temperature, habitat you've chosen, and the other fish that they'll live with eventually.
Are corydoras friendly?
Yes, corydoras are sweet and gentle fish. They particularly like spending time together, but get along with many others as well. In some cases, you should not buy just one as they'll get lonely. Instead grab a pair of the same type and watch them become best friends. You'll often see them as bottom feeders, well, at the base of the tank, but cory cats also come up to the surface for air or food from time to time.

Read more
Is your fish tank for bettas too small? Here’s are the do’s and don’ts of betta care
Care tips to keep your new betta fish happy in the right size tank
A betta swims with plants in its tank

While the betta craze may have died down a little, you still see many of these beautiful blue fish in homes and in stores. It's true that they make great pets, even for a novice aquarist, since they don't require an overly extensive tank setup and often prefer to be alone. But just because they work well for a newbie doesn't mean you can dive in without any research. We're here with what you need to know about betta fish care and fish tanks for bettas. Here are the do's and don'ts for bettas.

What do I need to know about taking care of my betta fish?
Do research fish breeders
It all starts with the betta egg, and even the mom and dad. Just like with a puppy, you want to ensure your fishy has had a good life from hatching. There are tons of ethical breeders out there, but you can find some shady ones, too. In general, you want to avoid stores that have them crammed into tiny containers and cycled in and out every day. Do your research about local pet fish stores in your area or check out some of the more reputable ones online.

Read more
5 fantastic ways pets in a classroom benefit kids (and the best pets to get)
Learn which are the best pets for classrooms
Leopard gecko with smiling face

Gus, Copper, and Oliver-Clyde live busy lives at the Beck International Academy in Greenville, SC. When they aren’t playing in their enclosure the guinea pigs are hanging out with students at their desks or visiting other classrooms. In addition to spreading joy, middle school teacher Alexandra Jackson says that the guinea pigs have been an incredible source of growth and learning for her students.

Jackson acquired two of her school guinea pigs with help from The Pet Care Trust’s Pets in the Classroom grant program. These grants provide financial support to teachers for the adoption or purchase and maintenance of small animals in Pre-K through Grade 9 classes. Since its inception in 2010, the program has impacted more than 8.1 million students across the U.S. and Canada.

Read more