If it's been there for awhile, then it's probably trying to adjust to water parameters. As far as feeding, when I first got mine, I was told that I needed to feed it every 8-10 days with silversides. I did this for years. Being new to this sight too, the consensus seems to be that they get all the feeding that they need, with sufficient lighting of the right spectrum, and not from expired bulbs! I agree that it isn't necessary, but once in a while( once every month or two) couldn't hurt. I do think also, that constant feeding led
mine to get ridiculously large. Not necessarily a good thing, I'm now in a 180 and the only place it won't damage anything is in the front right corner! I've thought to trade it at my LFS
, and probably will end up doing that with the clown, but I've had them for years and don't really want to part with them! Good Luck, see what happens if you adjust your parameters...slowly!