i have 8 of them they range from 2-4 in. in a 100 gal brackish. they live with a puffer, dragon goby, upsidedown cat and 5 mollys to have babies or their lunch what ever happens first. i sware the targets don't sleep! they have chasted fish right out of the tank. they fight all the time. feeding time is crazy. they don't mess with the puffer or dragon. the rest is fair game! i love to watch them. each one has their own personality. just not sure how big thay get. when i got them in the beging of march they were less then a inch.