Search Results for: Pacific bluefin tuna
period, after which many (such as sharks ) became formidable marine predators rather than just the prey of arthropods . most fish are ectothermic ("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna
from water using gills or uses an accessory breathing organ to breathe atmospheric oxygen, has two sets of paired fins, usually one or two (rarely three) dorsal fins, an anal fin, and a tail fin, has jaws, has skin that is usually covered with scales , and lays eggs. each criterion has exceptions. tuna...
https://en.wikipedia.org/wiki/Fish