I've got 2 of these catfish on my Asian arowana tank. They like to go to the arowana's gills and scales, maybe they are cleaning the infested body parts, somewhat giving it a quick bath and, suprisingly, my arowana likes it a lot.
I currently own three Upside-Down Cats, all of them are great fish. They clean decorations, plants, gravel, and the sides of the tank. Mine are all doing great in a 75 L tank. In my experience they've eaten pellets, but they prefer frozen bloodworms. During the day they hide, but at night are energetic fish. They swiftly chase each other at night (for fun) which is great fun to watch. Note: these fish scrape themselves during cleaning (if scared) against decorations with sharp points. I recommend these fish to anyone, because it's a harmless, playful, interesting, and useful catfish.
My upside down catfish changes his color! When he is by a light-colored rock he goes light cream with brown spots, and when he swims up to the heater that is black he turns black with brown spots. Very interesting to watch. He swims in a 180 L tank with 2 frogs and 3 platies. They have all lived happily in the tank for 3 years now.
Just a fact about the true Upside Down Catfish, they feed on mosquito larvae in the wild, which hatch and lie at the top of ponds. This explains their habit of swimming upside down most of the time, it comes natural to them to feed like this. If you can manage to get live larvae, they love it!
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