valentini puffers are nearly compatable with almost anything other than valentini puffers "depending on the size of the tank". I agree though you dont want to add much more bc you need to feed the puffer shrimp/seaweed mix daily. 4 mabye 5 fish in a 30. With the valentini I would stick to four 3 in fish. My blue devil damsel is overly aggressive to my puffer, always harassing him during my hand feedings "swimming backwards and rubbing his fin on the puffer". Cannot wait to get rid of those little buggers. If I was stocking a 30 with a valentini I would get a blenny, a purple firefish, and if not fully satisfied a bangaii cardinal.