+2May need to specify which ones your looking into. Sharptoothbass keeps a good amount of them.
They'll be fine, they're greedy fish, I like them, don't put anything half its size with it, depending on body shape 3/4 should be avoided as well. They're not really territorial and even so don't fend to well. They max out at 17" supposedly but never seen one more than maybe 14". Will require a bigger tank than your 55g. Think you should focus on that before adding anything... anything specific you wanna know?Was gonna keep to goby and sun together. The Wolf may be sold. That Wolf is more skittish since I added the sun. The goby is ten inches.