Can Channel Catfish Live with Koi?

Whenever I go to a pond and garden center, I always see channel cats so I was really tempted to let them swim around with my koi. In some cases, they can actually be decent pond mates.

The problem, as I found out the hard way, is that the domestic albino variants you usually see in fish stores can grow to around 5 feet in length. Some material that I’ve read suggests they can get even bigger depending on what kind of food is avaiable for them in your pond.

At that size, they’re pretty free to swallow small and even medium-sized koi fish whole, which is exactly why you’ve got to be careful letting them live together.

So, can channel catfish live with koi? Yes if they are similar in size or the koi are larger. Full size channel catfish that are several feet in length should not be introduced into a koi pond. Instead, it’s best to get similar sized fish and let them grow up together.

Will Koi Eat Them?

I don’t normally see huge koi for sale in pond supply places, so it’s hard to imagine your garden variety koi fish eating a channel cat. It’s theoretically possible if your fish gets large enough or you’re trying to raise baby catfish.

Nearly every pond and garden expert I’ve come across cautions against leaving adult koi with immature other fish because of the possibility of the smaller ones being viewed as a snack.

Will the Catfish Eat My Koi?

This is a much bigger concern, simply because the fish involved are much bigger! An adult channel catfish can grow to lengths of 5 feet or even more, so they could theoretically swallow small koi whole.

Some garden experts I’ve followed consider the channel catfish to be a so-called questionable pond mate for koi, much like the more aggressive bullhead catfish and the very toothy Japanese catfish.

List of Catfish that can Live with Koi

Out of true catfish, there’s generally four species that cooperate well with koi fish:

  • Columbian Shark
  • Iridescent Shark
  • Bumblebee Catfish
  • Bandit Cory Catfish

If you’re like me, then those first two names really threw you off. While they’re called sharks by most pet stores, both the Columbian and the Iridescent are actually catfish that live relatively well alongside koi if you give them enough room.

In general, it seems that they survive well on the same food, but you want to keep your fish healthy. If one of these cats gets too large, then it might consider a sickly koi to be a nice snack!

Fortunately, if you’re keeping fish from these four species there’s a few ways you can reduce the risk of a fish between them and your koi.

How to Stop Koi and the Other Fish from Fighting

Overstocking is probably the number one cause of fish fighting with each other. If you have too many in one pond, then even your koi will fight with each other.

I’ve found that most people recommend a ratio of 10 gallons for water for each inch of fish you have stocked together. Add up the length of every fish you plan on putting it and then divide this number by 10 to find out how much water you need for all of them.

If you’re just starting out with young fish, then keep in mind that they’re probably going to grow a lot bigger so you might want to have even less than this until you’re sure how big they’re going to get.

How Big Will They Get?

Most experienced keepers I’ve seen say that female Jumbo koi can grow to around 30 inches long and weigh over 20 pounds. Japanese decorative koi, however don’t usually get much longer than 25 inches.

If you’re worried about the amount of room you have, then look into smaller domestic varieties. Most domestic koi usually stop growing after they get around a foot long.

What Should I Feed Them?

While I’ve tried a few different foods, it seems like a piece of advice given to me at a larger pet supply place has worked the best. Regular floating fish food that has around 28-36 percent protein is a good fit for catfish.

You could even go with a food that provides more protein than this. In many cases, koi and channel cats will enjoy the same flake food products.

Don’t overfeed them, but make sure there’s plenty for all your fish to avoid fights.

How Often to Feed Your Fish

Judging by what I’ve read from aquaculture specialists, you’ll want to feed newly hatched channel cats much more than adult ones. Assuming that your fish are developed, you’ll probably want to feed them around 4-6 times every week.

Young fish will need food several times a day. Once the temperatures start to drop, catfish have a tendency to eat much less.

You might want to switch to a high-protein sinking feed once it drops under 50°F or so.

How Long and Deep Should the Pond Be?

My first pond was way too small, and I figure that a lot of people probably start out this way. When I was having trouble, I found that a number of experienced koi and catfish aficionados recommended ponds to be no smaller than 1,500 gallons.

This means you’ll want it to be at least four feet deep if it’s dimensioned at somewhere around 7×8 or so. This gives your koi and catfish plenty of space to grow.

Depending on how many fish you have, you might want to have a pond as large as 15,000 gallons.

How to Help them Through Winter

Start reducing the amount of food you give them when you notice that they slow down with feeding. Your pond might soon start to freeze over, which could actually protect your koi.

Many experts have recommended not feeding at all during the coldest months. Those who find that their ponds are icing over completely may want to aerate the top, but it’s probably a good idea to leave at least some ice cover to help regulate the pond.

Those who live in warmer climates that have milder winters may need to feed once or twice a week during the winter months, but it’s still not the best idea to feed your fish whenever the temperature drops below 50° and stays there for an extended period of time.