Midas Blenny (Ecsenius midas) Breeding Guide

Breeding the midas blenny (Ecsenius midas): demersal nesting in the genus Ecsenius and why raising the planktonic larvae at home is rarely successful.

Overview

Ecsenius midas is a combtooth blenny (family Blenniidae) widespread through the Indo-Pacific from East Africa and the Red Sea to the Marquesas; it grows to about 13 cm and is a planktivore, often seen swimming in the water column alongside lyretail anthias, whose color it can mimic (Wikipedia). As an Ecsenius, it is a demersal egg-layer. Spawning of the genus is reported as relatively common in aquaria, but rearing the larvae has historically been extremely difficult, so home breeding is advanced.

Sexing

External sexing of Ecsenius midas is not documented in the consulted scientific sources. In the genus, a functional pair is recognized when two compatible fish occupy and defend a shared nesting hole, so behavior is the practical guide rather than fixed markings.

Breeding Setup

Ecsenius blennies shelter in rock and use crevices and holes as nest sites. A mature reef aquarium with abundant live rock and small-diameter tubes or holes a pair can defend provides spawning structure. Stable parameters in the species ranges (temperature roughly 24-27 C, pH about 8.1-8.4) support conditioning, and because the midas blenny feeds in the water column, frequent feeding helps maintain condition.

Spawning Behavior & Trigger

Like other Ecsenius, the midas blenny deposits demersal eggs and tends a nest. Aquarium accounts of bred Ecsenius report compatible pairs spawning every few days and tending a large nest of multiple egg batches attached to a surface, with hatching roughly five days after laying (Reef Builders). Eggs are guarded at the nest rather than broadcast into open water.

Egg & Fry Care

The limiting step is larval rearing. The first confirmed rearing of any Ecsenius (E. gravieri) was reported in 2014 after decades of failure, with a further commercial success on E. pulcher reported in 2024 (Reef Builders). Newly hatched larvae are tiny and pelagic and require very small live first foods; hobby sources indicate copepods such as Parvocalanus crassirostris may be needed before a transition to Artemia nauplii. No routine home protocol for Ecsenius midas is documented.

Common Challenges

Spawning is the easy part; the planktonic larval phase is the bottleneck. Minute larvae, demanding live first-food cultures, and a long pelagic period have limited success to specialized hatcheries rather than home aquaria.