Whitemouth moray eels can squeeze into the tightest spots on the reef and are often seen with just the head sticking out. They’re easy to identify with their bright white mouths, which they’re constantly opening and closing. While this activity looks somewhat menacing, they’re actually forcing water over their gills in order to breathe. That’s not to say that, if you waggle your finger in the face of an eel, it won’t bite it off so, as with most creatures in the water, it’s best to keep at a reasonable distance and be respectful of them.