Crustacean - Copepods, from Ernst Haeckel's 1904 work Kunstformen der Natur.
Marine hermit crab Diogenes pugilator, using a shell of the dog whelk Nassarius reticulatus.
A Hermit Crab in a Glass Shell
Hermit crab in glass shell.
18 Amazing Underwater Macro Photos
Imperator Shrimp. This tiny shrimp often lives in a symbiotic relationship with several nudibranch species, it lives on their back and in the gills of the nudibranch – feeding on it’s feces. They also live on sea cucumbers, but then they have a slightly different colour. This shrimp is easy to miss because of it’s size.
The Ping Pong Tree Sponge, (Chondrocladia Lampadiglobus) lives more than 1.5 miles beneath the surface of the ocean and is carnivorous.