Actually long is better since it gives the fish more room and has much more bottom area. What kind of loaches are they? I don't know what stick cats are, but I think 4 cats and 3 loaches will fill the bottom out. If they're kuhli loaches, the bottom have room for a few more (but not really, since you've got so much in the top), but other loaches are bigger so it's probably maxed out otherwise.