Nats and caribes are piranha but kept alone they turn into big babies, phagoes will allow 3 and a bagdad cat in a tank that size. Or go brackish and get a peir of archer fish for around $50Chad55 said:Those are all really good suggestions but this tank is at my dads and I was looking for something a little easier to take care of. It is my fault though because I did not explain myself. I am sorry because I was in a rush so it is my fault, but I couldnt find anything on the nat or carrib could somebody please explain? Thank you Chad.