How are ectotherms and poikilotherm the same?

Ectotherms and poikilotherms are similar in that both rely on external environmental temperatures to regulate their body heat. Ectotherms, which include reptiles, amphibians, and many fish, do not generate significant internal heat and depend on their surroundings to maintain their body temperature. Poikilotherms, on the other hand, are organisms whose body temperature fluctuates with the ambient environment, which can include both ectotherms and some endotherms that can have variable body temperatures under certain conditions. Essentially, all ectotherms are poikilotherms, but not all poikilotherms are necessarily ectotherms.