Cardinal Nippers

[holocron]

Hey,

I have 5 discus in with about 30 cardinals, and I see the cardinals from time to time nipping at the anal fins of the discus. The discus aren't too upset, but seem to shake them of by twitching their fins, kind of like a horse brushing flys away with its tail.

any idea what's going on here? is this going to be a bad thing over time?

thanks.

[ShinShin]

Cardinals have a mouthful of teeth and can be fin nippers. I hadn't really ever noticed Cardinals nipping fins on my discus when I had a planted tank. Perhaps your Cardinals are underfed.(?)