ah the blue cat... lovely bugger! get 6 or more in a species tank, they kick waaay more ass than pirahnas imho... much nicer to look at as well while they're not feeding.
there's another 'blue' whale cat that has white spots on it, it loses its blue color upon maturity, anyone knows exactly what that is? also, i've noticed this catfish doesn't swim around the tank at all, the exact opposite of the guys mentioned earlier...