Identification
The pearlfish is an elongated, translucent fish of 15 to 30 cm with an eel-like body without scales. Extremely slender, tapering to a pointed tail. Color is pale translucent to silvery. The mouth is relatively large with small teeth.
Ecology
The pearlfish has one of the most extraordinary lifestyles of any European fish: it lives inside the body of sea cucumbers. It shelters during the day in the sea cucumber's body cavity and emerges at night to hunt small crustaceans. The fish enters the sea cucumber through the anal opening, tail first. The name “pearlfish” refers to dead specimens sometimes found encapsulated as “pearls” inside shellfish.
In the Netherlands
The pearlfish is extremely rare in the North Sea. More common in deeper waters of the northeastern Atlantic and the Mediterranean.
