Q. One of the whiskers of my shovelnose catfish branches off at the top, making it look like a “y.” Is it deformed? Also, how do you wean a shovelnose catfish off of feeder fish? I fear feeder fish will spread disease in the fish aquarium.
A. Sorubim lima is the shovelnose catfish that you see most frequently in the aquarium hobby. This shovelnose catfish comes from South America, where it inhabits the entire Amazon River basin and its tributaries. Wildfish attain 18 inches in length, but individuals raised in captivity usually get to be about 15 inches at the most. Although normally nocturnal, this fish quickly learns that food is around for easy pickings during the day, and pretty soon it’s up and around, looking for food like any other fish. The branching of one of the whiskers is nothing to worry about — the opposite is usually the case, in that the whiskers often get damaged in transport. A lot of fish that have long whiskers have some variation in the splits at the end of the whiskers.
You are being a good FishKid in wanting to wean your shovelnose catfish off of feeder fish, as it is a waste of money, as well as a risk of introducing disease. Large predatory fish that have been fed live feeders for a while often will not eat when offered something other than live fish. But don’t worry – very few have ever starved to death because they refused to eat something other than feeders. Some marine fish, such as butterflies and some angels, are “obligate feeders,” which means that the only thing they recognize as food is a certain species of coral or sponge. These fish will starve without the specific food source they need.
Large predatory catfish are opportunistic feeders, and while they prefer to catch something live, if times get tough they will eat dead fish. The best way to get your catfish to switch is to stop offering it live feeders. Go for four or five days without feeding it anything. Then try something like frozen white fish or shrimp, or the small frozen fish sold in your local fish store. To get it interested in the new food, get a long piece of clear, rigid aquarium tubing (the thin stuff about one-eighth inch in diameter). Cut one end to a point, and impale the food on that end. Then, very gently and quietly, waft it in front of your shovelnose. Initially it may turn its nose up at this new food, but you just have to outlast it in the stubbornness category. If it doesn’t take it after five minutes or so, just try again the next day.
There also is a form of frozen fish food available that looks like a 1-inch-long fish. This comes with some fine fishing line and a little pin. The idea is to thaw it out a bit, hook it to the end of the line and drop it in front of your fish. I’ve seen this demonstrated in a store, and it works well. Whichever method you choose and whatever food substitute you decide to feed it, eventually your shovelnose catfish will make the changeover from feeders to frozen fish.