Elysia pusilla is nearly always found associated with Halimeda algae. It can be common, but it blends in well on its algae host and can be very hard to see. We have found specimens at Kwajalein and Enewetak Atolls on lagoon reefs from 5 all the way down to 65 meters depth. It has also been photographed at Majuro by Ken Cone and Beth Van Zummeren. It is quite variable in color, and the numerous photos below show some of this variation. This species is sometimes seen listed in the genus Elysiella. Elysia pusilla was first reported in the Marshalls from Enewetak Atoll by Johnson & Boucher (1984).
Immediately below is the Majuro specimen.
Despite the odd coloration, we think this is the same species.
The specimen below from a Kwajalein Halimeda patch on 19 July 2009 had a lot of blue.
The specimen below was found on 9 August 2009 in a Kwajalein lagoon Halimeda patch.
This species also comes in a more flattened body form.
They can stretch out quite a lot.
A more flattened variety.
Created 2 February 2007
Updated 14 August 2021