Tanaka's Possum Wrasse

Tanaka's Possum Wrasse

Tanaka's Possum Wrasse (Wetmorella tanakai) is a tiny, jewel-like reef fish that lives a quiet, hidden life among the rocks. Patterned in deep red with pale bars and false eyespots near the tail (which help confuse predators), it is rarely seen out in the open, preferring the shadows of caves and overhangs. Peaceful, reef-safe and undemanding once settled, it is a charming choice for a calm nano or community reef — for keepers happy to be patient with a shy, cryptic fish.

Its secretive nature is the main thing to plan around: in a busy or aggressive tank it will simply never appear.

Natural Habitat & Origin

Wetmorella tanakai is found on Indo-Pacific reefs, where it lives deep within the reef structure — in caves, crevices and beneath overhangs — emerging only briefly to forage for tiny prey. Its cryptic colouring and retiring habits keep it safely hidden.

In the aquarium it strongly benefits from plenty of live rock with caves and dark crevices to shelter in, and a calm, established environment.

Care Requirements

Maintain stable marine conditions: salinity around 1.024–1.026, pH 8.1–8.4, and a temperature of about 24–26°C (75–79°F). Reaching only about 6 cm (2.5 inches), it is well suited to nano and small reefs of around 75 litres (20 US gallons) or more, provided there is plenty of rockwork. A secure lid is wise. It is reasonably hardy in a calm, mature tank, though it can be hard to spot.

Diet & Feeding

Tanaka's Possum Wrasse is a micro-carnivore, feeding on tiny crustaceans and other small invertebrates picked from the reef. In the aquarium it accepts small meaty foods — frozen mysis, enriched brine shrimp and finely chopped seafood — but as a shy feeder it benefits from a mature tank with natural microfauna and from gentle, regular feeding where it can reach the food from cover.

Behavior & Temperament

This is a peaceful, retiring fish that poses no threat to tankmates and spends most of its time hidden, especially when newly added. Over time it grows a little bolder. It can be kept singly or as a pair. Its shyness, not aggression, is the limiting factor — a calm tank is essential for it to thrive and be seen.

Tank Mates

Keep it only with small, peaceful reef fish — gobies, firefish, small calm wrasses, cardinalfish and similar — and avoid aggressive or boisterous species that will keep it permanently hidden or outcompete it. It is fully reef-safe, leaving corals and ornamental invertebrates alone, and suits a peaceful nano or community reef well.

Breeding

Wetmorella tanakai is a pelagic spawner and is not bred in the home aquarium; trade specimens are wild-collected. Pairs may form in a suitable, peaceful tank.

Common Health Issues

Tanaka's Possum Wrasse is reasonably hardy in the right setting but can decline if outcompeted for food or kept in a stressful, busy tank. Like all marine fish it can be affected by marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium ocellatum). Provide ample cover, a calm community and gentle regular feeding, quarantine new arrivals, and this charming, secretive little wrasse can be a delightful and unusual addition to a peaceful reef.