dude, go with the archers, there sweet. brakish smakish lol. my archers in pure freshwater an dyes they shoot down there prey. a 50 gal should be ok for a few of them. they grow so damn slow you'll be fine with them til u prolly get bored of them. i have one in my 100gal and he's so fast i doubt he'll get eatin by other fish only thin that ever happened to my archer is his tail got nipped by my bichir. grew back and he's been fine since. try it out.