Phyllidia varicosa Care Guide

Phyllidia varicosa is a warty Indo-Pacific nudibranch that feeds on sponges and releases toxins when stressed, making it unsuitable for community tanks.

Overview

Phyllidia varicosa is a dorid nudibranch of the family Phyllidiidae, described by Lamarck in 1801. It is a large sea slug reaching at least 115 mm in length, recognised by three to six longitudinal tuberculate ridges along the back. The ridge bases are blue-grey with yellow-capped tubercles, and a black stripe runs along the sole of the foot. The species is distributed throughout the Indo-West Pacific, including the central Pacific and the Red Sea.

Taxonomy

Family: Phyllidiidae
Genus: Phyllidia
Scientific name: Phyllidia varicosa
Authority: Lamarck, 1801

Habitat

The species inhabits tropical reefs across the Indo-West Pacific. Like other phyllidiids it is associated with sponge-rich substrates where its prey occurs. Its bright black, white and yellow pattern functions as aposematic (warning) coloration; juvenile sea cucumbers of the species Pearsonothuria graeffei are reported to mimic this colour pattern for protection.

Aquarium requirements

Water type: saltwater (marine reef)
Minimum tank volume: 100 L
Temperature: 24-26 °C (75-79 °F)
pH: 8.1-8.4
Specific gravity: 1.024-1.026
Alkalinity (KH): 8-12 dKH
Adult size: 4-8 cm in aquarium records; wild specimens reach 11.5 cm
Lifespan: about 1 year

Diet

Phyllidia varicosa is a specialist carnivore that feeds on sponges. This narrow dietary requirement is the main reason it rarely survives in captivity: most aquariums cannot supply a continuous source of the specific sponges it consumes, and the animal slowly starves.

Compatibility

The slug itself is not aggressive, but when stressed or injured it releases toxic chemicals into the water. In an enclosed aquarium these toxins can harm or kill fish and other invertebrates. Because of its specialist diet and chemical defence, the species is not recommended for mixed community or reef tanks and is best left in the wild.