The half beaks, and needle fish are notorius for that, hujetas and cachorros are better, african pike characins and pike topminnows aren't bad, but all do better with plants and a dimmer switch for your lights.mikehawk said:Barracuda spook easily and aren't that bright. They need a pretty big tank. I just watched my friend's barracuda skin its nose because somebody walked by the tank (55gal) and the fish took off and rammed its face into the glass.
I wouldn't put them in the 20gal if I were you.