Cold smoked tuna fillet. Yellowfin tuna is a mackerel-like species that includes all tuna-like species. Tuna is a warm-blooded fish and has red-colored fish meat. Yellowfin tuna has a cobalt blue to black back with a characteristic long yellow belly and dorsal fin. Yellowfin tuna can reach a length of 230 cm with a weight of 180 kilos. The yellowfin tuna swims to a depth of 250 meters, has a lot of power and can reach a speed of 80 km per hour. It is striking that the tuna does not have a swim bladder, which would make it sink like a brick when it stops swimming. That is why the tuna is constantly moving. Yellowfin tuna is a very fast growing fish and can reach the age of 9 years. High-quality tuna is found in Panama, Mexico to California and Hawaii.