The creature moving around the tank using its pectoral fin is a baby clown wrasse.  It eats food found under sand and small rocks. Using its mouth it blows on sand and moves small rocks. When in danger or in sleep, it buries itself in sand.

Patterns on its body vary from baby to an adult, male to female. The baby clown wrasse is a popular aquarium fish.

It is a relatively large type in the wrass. Some of them can exceed 1 m but usually, they are about 60 cm in length.