lower vertebrates

Are All Fish Poikilotherms? In fish, most species are poikiolothermic ectotherms, but Antarctic and deep sea living species are homeothermic ectotherms. Are all fish poikilotherms except? Poikilothermy is characteristic of lower vertebrates (fish, amphibians, and reptiles), but not of birds and mammals. Which animals are not poikilotherms? Aves and Mammals are homeothermic. They maintain body