For the most part they grow 1/2" a month. And yes stress is the biggest factor. The reason I fed veggie diet was because it helps to keep the digestion goin. But after a couple months of keeping mine I would intro massivore, which is a large part of my fish room diet. This male I have eats about 5 massivore pellets a day along with some soft krill pellets. He is a real pig and will try just about anything. He won't eat talapia or shrimp but love bloodworms lol