i bought 5 piraya for my 240 in mid-august. they were all the same size (2"-3"). all of them have been growing nicely, and of course there is a biggest one (approaching 6") the mid-sized ones, around 5", and a LITTLE one, hes still about 3" long! what gives? i feed them regularly, do water changes, and they have lots of room. and all the others are growing nicely. im worried that hes going to end up lunch if he doest grow soon... oh and i watch them eat, and he always gets food, he comes away looking very full actually.