Antennarius commerson is a small fish which grows up to 38 centimetres (15 in). Like other members of its family, it has a globular, extensible body. The soft skin is covered with small dermal spinules. Its skin is partially covered with a few small wartlike protuberances, some variable shape scab-like blotches and a few small eye-spots (ocelli) reminiscent of the holes in sponges. Its large mouth is prognathous, allowing it to consume prey as large as itself. The coloration is extremely variable as they tend to match their environment. Frogfish can change their coloration in a few weeks. However, the dominant coloration goes from grey to black passing through a whole range of related hues like cream, pink, yellow, red, brown and also usually with circular eye-spots or blotches that are darker than the background. Juvenile specimens can easily be confused with relatives Antennarius maculatus and Antennarius pictus. To distinguish these species, A. maculatus usually has red or orange margins on all fins, while A. maculatus has numerous warts on the skin, and A. pictus is covered with ocelli. A. pictus has three eyespots on its caudal fin.