Morphology and Innervation of the Fish Heart

Fish have adapted extremely successfully to the extremes of the aqueous environment, with the teleosts being outstanding in this respect. Amongst the class Pisces are pelagic species which must maintain certain swimming speeds in order to remain buoyant, species which migrate over thousands of miles, abyssal species living in waters with markedly reduced oxygen content, species living in the subzero waters of the Antarctic and also the obligatory air—breathing species of the tropics. Even i...