They are saltwater, medium size puffers (6" max. as far as I know) also known as a toby. Not really aggressive except toward invertebrates and other tobies (can fin nip but mine was afraid of the goby when I introduced him). Need meaty foods such as shrimp, mussels, clams, brine shrimp, krill and should also be fed seaweed (they love julian's sea veggies green seaweed- mine will eat it until he poops green if you let him). Will eat hard corals, chew on live rock (for the aglae- if you give them sea veggies, they chew the live rock less). Need clean water like any other puffer.