About six months ago i got a bunch of juvies that were all about the same size. I got some labs, a couple differant kinds of zebras, some kenyis, a bumble bee and a rusty. Since i got them, all of these fish have about tripled in size but the labs are still a LOT smaller than the other fish i baught at the same time. they are only about half the size. Are labs naturally slower growing, smaller fish or is there something wrong with mine?