the sandfish has the same basic anatomy as most other species of sea cucumber. their bodies are elongated and cylindric, and relatively stubby. their dorsal side can range in color from a grey-brown to black, with darkened wrinkles across the body and small black papillae from end to end. they are counter shaded with a lighter ventral side, which is relatively flat. they have a mouth located on the ventral surface at one end of the body, considered the front end. like other sea cucumbers, they use feeding tentacles which protrude from the mouth. sandfish have around 20 short tentacles. on the opposite end the anus is found on the dorsal side. they can grow up to an average length of 22 cm with the largest reaching up to 40 cm, and reach maturity around 16 cm or 200 grams with some growing as much as 300 grams in one year. it is unknown how long they live undisturbed, but they can live to at least 10 years.