It lives among other organisms on the seabed and occurs in both shallow and deep water in many parts of the world.

[2] The male Caprella equilibra is about 22 mm (0.9 in) long while the female is about half that size.

The type locality is the United States, where it is present on both coasts, and the range includes Argentina, Australia, Japan, Madagascar, Malaysia, New Zealand, the Philippines, South Africa, West Africa, Western Europe and Venezuela.

Its typical habitats include living concealed among seagrasses, sponges, green and red algae, hydroids, octocorals, bryozoans and colonial tunicates.

[2] It is mainly a detritivore but has a more varied diet than some other caprellids, ingesting some of the hydroids to which it clings and even feeding on the plankton collected by the polyps.