Common name	Scientific name	Family	Status	Weight	Countries
Green hydra	Hydra viridissima	Hydridae	Not recorded	Not recorded	Not recorded
Grey hydra	Hydra oligactis	Hydridae	Not recorded	Not recorded	Not recorded
White hydra	Hydra vulgaris	Hydridae	Not recorded	Not recorded	Not recorded
Alberta hydra	Hydra canadensis	Hydridae	Not recorded	Not recorded	Not recorded
Slender hydra	Hydra circumcincta	Hydridae	Not recorded	Not recorded	Not recorded
Jersey hydra	Hydra hymanae	Hydridae	Not recorded	Not recorded	Not recorded
Oregon hydra	Hydra oregona	Hydridae	Not recorded	Not recorded	Not recorded
Utah hydra	Hydra utahensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra baikalensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra beijingensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra berberina	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra campanulata	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra cauliculata	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra convallaria	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra crataegaria	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra daqingensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra digitalis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra ethiopiae	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra hadleyi	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra harbinensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra iheringi	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra intaba	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra intermedia	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra japonica	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra javanica	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra liriosoma	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra madagascariensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra magellanica	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra mariana	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra minima	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra mohensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra opercularia	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra oxycnida	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra paludicola	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra paranensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra parva	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra plagiodesmica	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra polymorpha	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra pyraria	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra robusta	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra rutgersensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra salmacidis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra sinensis	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra stentoria	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra thomseni	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra umbellaria	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra umfula	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra zeylandica	Hydridae	Not recorded	Not recorded	Not recorded
Not recorded	Hydra zhujiangensis	Hydridae	Not recorded	Not recorded	Not recorded