Many of the fish reacted aggressively towards their reflections at first (engaging in “mouth-fighting”), apparently seeing the reflection as another cleaner wrasse in their space. But ...

The slingjaw wrasse, Epibulus insidiator, is a species of wrasse with an astounding jaw. Its mouth can extend over half the length of the fish's body. The fish can protrude its jaws longer than ...

On seeing these colors, the itchy “client” strikes a specific pose, allowing the wrasse to snake across its body, mouth, and gills, picking off parasites and dead skin along the way.

In the course of studying wrasse skulls, an evolutionary biologist found a parasite hiding inside a fish’s mouth. And not only had the louse eaten the fish’s tongue – it effectively replaced it.

Fish lips may be fixture of the selfie generation, but for one tropical fish, a fleshy pout helps them survive. The tubelip wrasse (Labropsis australis) relies on self-lubricated lips to eat ...

In another shot, it appears that the diver is being ejected from the fish's mouth. The Napoleon Wrasse in question is a popular fish known to locals as Wally.