Anectotherm is an organism in which internal physiological sources of heat are of relatively small or of quite negligible importance in controlling body temperature.
A homeotherm is an organism that maintains its body temperature at a constant level, usually above that of the environment, by its metabolic activity.
Thus, an ectotherm is a homeotherm.
For example- certain tropical fishes in coral reefs have stable internal temperatures. Similarly, desert lizards maintain their body temperatures.