These tuna do not consume as much fish in their diet as other tunas, and will eat the tiny larvae of stomatopods (king shrimp or mantis shrimp), true shrimp, and crabs, as well as small fish. They do, of course, also eat juvenile and adult fish and squid. They are a short-lived, fast-growing species; a 5 year old fish would be considered old. They reach sexual maturity at two years old, and spawn in the open sea during the summer. Blackfin tuna are a warmer-water fish, preferring water temperatures over 68°F (20°C). What they lack in size, they make up for in numbers and willingness to bite.
Compiled from: Wikipedia (http://en.wikipedia.org/wiki/Blackfin_tuna)