You could be attacked by a shark if you went swimming in Lake Ontario in water less than four feet deep. The Basking Shark is the largest animal that has ever lived. The Thresher Shark uses its tail to herd fish into ever-smaller circles to facilitate feeding. Great Whites will attack boats and people. Bony marine fish uptake oxygen and loose carbon dioxide and salt through their gills.
All fish have swim bladders which they can use to voluntarily enhance or diminsh their buoyancy.
Bony fish lay about 1000 eggs during their lifetimes. Larval mortality rates are mainly determined by how close fish larvae are to a swift current when they hatch. Salmon spawn in the same stream in which they hatched. Fish evolved before dolphins. Hammerhead sharks and tunas are both kinds of fish.