Are you looking for a suckerfish to keep your aquarium clean? Many people automatically turn to plecostomus catfish (or plecos), thinking that they’ll magically vacuum up all the fish poop and debris in the tank. Before you make the purchase, let’s talk about this amazing animal, their care requirements, and whether or not plecos are the right pet fish for you.
Plecostomus is the common name given to the Loricariidae family of armored suckermouth catfish that come from Central and South America. The common pleco (Hypostomus plecostomus) is often sold in pet stores as a cheap cleaner fish. However, this 3-inch baby eventually grows up to be a nearly 2-foot beast with a surprisingly large appetite (and matching waste load). We strongly advise against getting monster fish unless you are prepared to keep them for their entire lives because they are nearly impossible to rehome. Also, do not release your common pleco into the wild because they are a highly invasive species and can do a lot of damage to the environment.
Thankfully, there are much smaller plecos that are better suited for the average home aquarium. Bristlenose, rubber lip, and clown plecos are all beautiful catfish that stay between 4 to 6 inches in length. They may cost a little more than the common pleco, but their manageable size and smaller food bill will more than make up for it in the long run.
Plecos are known for their armored bodies and distinctive suckermouths.
In general, their water parameters are fairly similar to other tropical fish. They prefer a heated aquarium around 74 to 80°F (23 to 27°C), and they can live a broad pH range of 6.5 to 7.8. Since most plecos are nocturnal, they greatly appreciate any hides or cover you provide to keep them out of the light. You also need to do regular tank maintenance to keep the nitrate levels at 40 ppm or below. (If you’re not sure what nitrates are, read our article on the aquarium nitrogen cycle.)
As for tank size, the 4- to 6-inch plecos we mentioned previously can be housed in 20 to 29 gallons of water or more. However, the common pleco should probably start in a 75-gallon tank and eventually move up to 180 or even 500 gallons. These enormous aquariums are not feasible for the average fish keeper, which is why we strongly recommend the smaller species.
Columbian zebra plecos (Hypancistrus debilittera) have a striking pattern and only grow to 4 inches long.
Although plecos are known as cleaner fish, scavengers, and algae eaters, they must be fed a regular diet consisting of high-quality fish foods. Think of it like having a pet dog. Yes, the dog will eat any scraps that fall to the ground, but they should still have daily meals consisting of actual dog food.
In the same way, these catfish need proper foods that adequately meet their dietary requirements. People tend to only give them algae wafers, but most plecos prefer well-balanced meals consisting of a wide variety of foods, such as frozen bloodworms and Repashy gel food. Do some research on your particular species because not all plecos eat the same thing. Some graze on algae and vegetation, some like to rasp on driftwood, and others crave more protein. (While many plecos are safe for plants, bristlenose plecos are known to sometimes snack on sword plants.) Since the majority of plecos are nocturnal, a good practice is to feed them when the lights are off so that they get a chance to feed while the other fish are less active.
A problem we often hear from new pleco owners is, “I don’t know why my fish died. I gave it one algae wafer every night.” Let’s go back to our pet dog analogy. If you feed your puppy 1 cup of food every day, he will likely require more than 1 cup when he reaches adulthood. Similarly, your adult pleco needs more food than a juvenile to support its larger body. A good rule of thumb is to aim for a slightly rotund belly. If the abdomen is sunken in and the fish is underweight, try increasing the amount of food. If its stomach is too swollen, it could be eating too much or constipated from an overabundance of leftover food in the tank. If you see lots of long, stringy pleco poop, nitrates could be building up to toxic levels, so make sure to vacuum the substrate and do a water change. (Download our guide to water changes to figure out how often you should clean your aquarium.)
Observe the roundness of your pleco’s belly, and adjust its food portion size accordingly to maintain a healthy weight.
As mentioned before, plecos vary in their food preferences, but none of them live solely on feces. While they may occasionally eat some while scavenging in the substrate, there is not enough sustenance in the fish waste for them to survive. Remember that plecos are not just cleaners but also living animals that require proper nourishment.
Plecos will be fine with almost any peaceful, community fish that isn’t big enough to eat them. Likewise, do not add any fish that are small enough to fit in the pleco’s mouth. Usually, these catfish are scavengers and won’t eat other animals unless they have already passed away. There are reported cases of plecos sucking on another fish’s slime coat, but this seems to mainly occur with larger plecos that aren’t getting enough food. Keep a smaller pleco, feed it well, and you shouldn’t have this problem.
Many smaller plecos can live together with other peaceful community fish like neon tetras.
Can two or more plecos be kept in the same tank? It depends. Some species (especially the males) can be territorial towards their own kind or other bottom dwellers, so research their behavior and ask fellow hobbyists about their experiences. Smaller species like the bristlenose pleco can be kept in multiples as long as you aim for more females than males and provide plenty of caves and hides for everyone to choose their favorite.
Bottom line: buy the right pleco that will, even at adult size, fit the size of your aquarium. Read online articles and visit social media groups to research their care and diet requirements. Ultimately, you are responsible for cleaning your fish tank, but if you’re looking for some little helpers, check out our popular article on top 10 clean-up crew members: