Lizardfish
Lizardfish have one of the best smiles underwater - they just love showing off their nice white teeth.
They are quite easy to approach as they like to think of themselves as masters of disguise. Although they're quite easy to spot, they'll stay completely still as you get closer and closer. They're convinced you haven't seen them until the very last moment. Then when it's obvious they've been spotted, they'll suddenly dart off, only to stop a few metres away where they think they're invisible once more - Lizardfish aren't the brightest fish around.