Breeding Trimma okinawae (Orange-Red Pygmy Goby)

Trimma okinawae is a tiny Western Pacific pygmy goby and a bidirectional sex changer. It is a benthic spawner, but no validated aquarium larval-rearing protocol exists for this species.

Overview

Trimma okinawae (Aoyagi, 1949), the orange-red pygmygoby, is a tiny Western Pacific goby ranging from the Ryukyu and Ogasawara Islands to Rotuma, the Rowley Shoals and the Great Barrier Reef. FishBase reports a maximum size of 3.5 cm SL over a depth range of 8-35 m, with the fish hovering, often upside-down, in small caves of clear coastal reefs near sponges and forming small loose groups.

Sexing

FishBase identifies Trimma okinawae as a bidirectional sex changer, meaning individuals can transition between female and male in either direction. Because sex is socially flexible and the fish is very small, fixed external sexing is not practical; a functional pair instead resolves from the social group.

Conditioning

This pygmy goby is a micro-predator that takes very small planktonic and benthic foods. In a nano reef, frequent feeding of fine meaty foods supports condition, and cave structure that lets the fish hover and shelter reflects its natural microhabitat.

Breeding Setup

A stable nano reef with caves and overhangs in rock or coral matches the species' preference for small reef recesses. Knowledge-base parameters are temperature 24-26 degrees C, pH 8.1-8.4 and moderate flow. Maintaining a small group allows the social system to establish a breeding pair.

Egg & Fry Care

FishBase classifies Trimma okinawae as a benthic spawner, so eggs are attached to a hard surface within the cave. There is no documented account of egg-care duration, hatching time or successful larval rearing for this species; the very small larvae and lack of a feeding protocol are the main barriers to captive production.