David Fleetham / Cleaner wrasse (Labroides dimidiatus) swimming alongside Golden damsel (Amblyglyphidodon aureus) looking for parasites, Fiji, Pacific Ocean.

Alex Mustard,Alex Mustard / A portrait of a small Candy stripe shrimp (Lebbeus grandimanus) in front of its host pink anemone (out of focus because of the magnification). Browning Wall, Browning Pass, Port Hardy, Vancouver Islan...

Sergio Hanquet / Shrimp (Trachycaris restricta), close up. Tenerife, Canary Islands.

Sergio Hanquet / Shrimp (Trachycaris restricta), close up. Tenerife, Canary Islands.

Sergio Hanquet / Red-backed cleaner shrimp (Lysmata grabhami) on sandy sea floor. Tenerife, Canary Islands.

Sergio Hanquet / Red-backed cleaner shrimp (Lysmata grabhami), view from above. Tenerife, Canary Islands.

Sergio Hanquet / Red-backed cleaner shrimp (Lysmata grabhami) head, close up. Tenerife, Canary Islands.

Sergio Hanquet / Red-backed cleaner shrimp (Lysmata grabhami). Tenerife, Canary Islands.

Sergio Hanquet / Red-backed cleaner shrimp (Lysmata grabhami). Tenerife, Canary Islands.

David Hall / Banded tozeuma shrimp (Tozeuma armatum) on Black coral (Antipatharia). Komodo, Indonesia.

Pascal Kobeh / Eyespot shrimp / Green marble shrimp / Spotted marbled shrimp (Saron sp., may be Saron neglectus) hidden in coral, Sulu sea, Philippines

Jordi Chias / Shrimp (Chorismus antarcticus) Antarctic Peninsula, Antarctica.