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. This species is often seen listed in the genus Elysiella.
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.
Created 2 February 2007
Updated 11 December 2011