Janitor Fish for Ponds FAQ: 19 Things to Know

Janitor Fish, also known as Pterygoplichthys disjunctivus, are small and spectacularly colored which makes them great for aquariums but be warned before you use them in your pond. Though they do clean ponds they can harm other fish and are invasive in some environments.

Here are 19 things you need to know about janitor fish before deciding to buy one.

What Is a Janitor Fish? Why Is it Called Janitor Fish?

Sailfin catfish are often called janitor fish because they scavenge the ponds they live in and eat dead or discarded material. In this way, they sort of clean up their environment.

Can Janitor Fish Live in Ponds?

Ponds are the native environment for janitor fish, so they usually thrive in them. Enthusiasts will often put them into artificial ponds or rivers that they dig.

Can I Put Janitor Fish Live With Koi?

While you can have janitor fish in the same pond with koi, you need to make sure there isn’t a big size difference between them because janitor fish may eat koi otherwise.

What is the Value of Janitor Fish?

Depending on the age of the fish, it could be yours for as little as $5-6, but some cultured mature fish will actually cost over $50.

Is Janitor Fish Good for Aquarium?

Certain janitor fish will grow far too large for an aquarium, but those that don’t will help to keep the environment clean.

Is Janitor Fish Poisonous?

While the fish themselves aren’t poisonous, their scavenging activities mean that they might have consumed something toxic so you don’t want to eat them usually.

Fish markets in some parts of the world commonly stock safe-to-eat wild-caught janitor fish, but you wouldn’t ever want to eat a domestic one taken out of a koi pond.

Does Janitor Fish Eat Poop?

Even the hungriest sailfin catfish aren’t going to eat poop from other fish, so you’ll still have to clean this up yourself. People who add them to a pond in the hopes that they’ll clean up droppings are in for a rude awakening because all they’ll do is add more of their own!

What is the Scientific Name of Janitor Fish?

Pterygoplichthys is the scientific name for their genus, and several species belong to it. Common names for them include janitor fish, sailfin catfish, and several other terms that all reference either their shape or their habit of eating disposed of material.

What is the Predator of Janitor Fish?

Since they’re scavengers who exist outside of the normal food chain, there really isn’t much that eats janitor fish in most situations. That’s why they’re able to take over ponds in areas where they’re invasive.

Scientists have been looking for and debating what kinds of fish might seriously eat janitors, and others believe some predatory birds might regularly snack on them.

What is the Cause of Janitor Fish?

Pet owners who didn’t take care of their animals and let them loose introduced these fish to rivers in Nevada and Texas. The exotic food market may have had something to do with them as well.

Never dump your pet fish into a wild waterway, because you have no way of knowing exactly how they’re going to interfere with the native populations.

Why Are Janitor Fish Invasive Species?

They’re not native to Texas, Nevada, Hawai’i, or Florida, and therefore have grown out of control in those states. According to a 2006 study published in the Zootaxa journal, populations have become solidly established in them.

Does Pond Algae Kill Janitor Fish?

Certain types of toxic algae can kill them, but most will actually serve as a food source that further nourishes them. The fact that sailfin catfish can survive by eating so many different foods has contributed to their invasive status.

Are Janitor Fish Aggressive?

Normally, janitor fish shouldn’t be very aggressive. The problem is that, like many fish, they’ll eat any other fish that tends to be smaller than them. That usually causes problems in koi ponds, where smaller immature koi run into larger janitor fish and look like a food source.

What Fish Can Live With Janitor Fish in a Pond?

Other catfish and koi can normally live with janitor fish as long as you don’t have too many of them and they aren’t too different in size. When they start to compete for resources or look small enough to be a snack, other fish could be swallowed by janitor fish.

In certain situations, large koi fish have actually swallowed up small janitor fish as well, so size really does matter in this case.

What is the Specific Effect of Janitor Fish on Biodiversity?

Areas with native janitor fish populations experience an overall increase in biodiversity as a result of their own existence as well as the fact that they aid in the decomposition process. They have a net negative impact in areas where they’ve taken over waterways that wouldn’t normally have them.

As early as March 2001, the Southwestern Naturalist scientific journal was reporting biodiversity-related problems as a result of their introduction in Texas and Florida.

How Does an Increasing Number of Janitor Fish Affect Other Fish in the Bay?

Eventually, janitor fish can crowd out other fish if they’re competing for resources. Since few predators regularly consume adult ones, this can become a serious issue in a larger bay.

Is it Safe to Eat Janitor Fish?

Wild-caught and commercially farmed janitor fish are normally safe to eat, but some from domesticated supplies may have ingested potentially dangerous material and should be avoided.

Can Janitor Fish Live Without Air Pump?

Depending on the size of the tank, janitor fish could theoretically live without an air pump, but this usually should only be tried in larger ponds. Aquarium-kept janitor fish usually need a pump and filter.

Does Janitor Fish Eat Tilapia?

Generally, janitor fish won’t touch tilapia that are kept in the same enclosure as them. They will, however, eat these fish if they’re considerably smaller than them.

This tends to be a theme when caring for a pond, so you’ll want to keep this general rule of thumb in mind no matter what kind of fish you’re raising.