ive had 2 for a few months now one is spotted and the other is the one with the lines down its side and neither of them seem to be growing. how fast should they grow and how big do they get. their about 3" and 4"
Pimelodus pictus tops out at about 5 inches or so. It's also a schooler. Get more (4+) and they will be more active, eat more, and grow faster.
Your 'striped' Pimelodus (which could be any of, oh, 4 species), I have no clue. Most pimelodus top out at between 6 and 12 inches. Get a latin or pictures and we can properly ID a size.