And pretty soon die from either lack of oxygen in a betta bowl, or die due to stunting. True that the outside of the fish (skin, bones etc) will stop growing, but the internal organs won't, and they'll eventually get crushed by the limited space, so the fish ends up with it's organs getting crushed, and in some cases, the fish splitting open like an overcooked sausage. If you honestly believe what you just said, then you need to strongly reconsider what hobby you are in.That pacu is only that big due to the enormous tank, but if you buy them small and raise them in a betta bowl, it'll just stay nice and small....and live happily ever after in that betta bowl