Breeding Honey Blue-eye (Pseudomugil mellis)

Breeding the endangered Pseudomugil mellis: sexing by male fin bands, plant spawning with 40-125 eggs over 7-9 days and fry care.

Overview

Pseudomugil mellis is a small Australian blue-eye from wallum heathland in southern Queensland, found in tannin-stained creeks and coastal dune lakes from around Brisbane northward. FishBase gives a maximum standard length of 3.5 cm, and Wikipedia notes the largest recorded male at 3.8 cm. It is listed as Endangered by the IUCN and as Vulnerable under Australia's national legislation, so captive breeding has conservation value. The fish forms schools of 25-70 individuals.

Sexing

Males have distinct black submarginal bands and white margins on the dorsal, anal and caudal fins, whereas females have transparent fins. Both sexes show the blue eyes and blue cheeks that give the genus its name.

Conditioning

Females mature early, at about three months or 1.5-2 cm standard length. The species mainly eats algae supplemented with insects and other aquatic invertebrates, foraging at the surface, so condition the group on small varied foods before spawning.

Breeding Setup

• The species spawns in submerged vegetation, so provide fine-leaved plants or spawning mops.
• FishBase gives a pH range of 6.0-8.0 and hardness of 5-12 dH, matching its tannin-stained habitat.
• FishBase lists a temperature range of 24-28 degrees C.

Spawning Behavior & Trigger

Males establish territories where spawning occurs, and spawning takes place from spring through summer. Females release 40-125 eggs over 7-9 days, generally depositing them at the base of aquatic vegetation; the demersal, adhesive eggs attach to plants rather than being released all at once.

Egg & Fry Care

The spawning medium can be moved to a separate tank to protect the eggs and fry. Following the pattern of the genus, the small fry begin on infusoria-type foods before moving onto free-swimming foods such as brine shrimp nauplii and microworm.

Common Challenges

Soft, tannin-stained water within the FishBase range suits this blackwater species. As an Endangered fish threatened by habitat loss and invasive species, keeping pure, well-recorded captive lines is valuable, and the small fry need tiny first foods and clean water.