Upsidedown Jellyfish Cassiopea spp.

The Upsidedown Jellyfish is native to shallow coastal lagoons, coral reefs and mangrove swamps of the Indo-Pacific Ocean, Caribbean Sea and warm western Atlantic waters.

There are several species in the genus, all with the same habits. They live in large aggregations. Each can grow to 10-30cm across and has a translucent brownish, yellowish or greyish bell.

Its name is because the adult jellyfish usually lies with its bell on the seafloor and its tentacles uppermost. This is because it has a simbiotic relationship with an algae which lives in its tentacles and needs sunlight to photosynthesize to provide the host jelly with additional food. Its tentacles also gather zooplankton.

It can swim but rarely does. It has a mild sting. Juveniles lay face down. They can reproduce asexually when young as budding polyps and sexually when in adult medusa form by releasing sperm (male) or eggs (female).