Mangrove Upsidedown Jellyfish

There was a large "garden" of them here. ( I assume they are C. xamachana because of habitat, I don't kow if at least some may be C. frondosa, as some look a little different. ) Anyhow, they lay upside down in shallow water where they can get plenty of sun to help the symbiotic algae living in their tissuesphotosynthesize.