Tateurndina ocellicauda

The Peacock Gudgeon, native to the slow-moving streams and rainforest pools of Papua New Guinea, is a fascinating species for the dedicated hobbyist. Its natural environment consists of soft, clear, and often tannin-stained water with minimal current and abundant vegetation. Replicating this biotope is key to their long-term health. An aquarium with a soft, dark substrate will highlight their colors, while a network of driftwood, leaf litter, and rockwork provides the necessary hiding places and territorial boundaries. Dense plantings, both rooted and floating, will help diffuse light and mimic the dimly lit conditions of their home waters, making them feel secure.

While considered peaceful, their social structure is complex. Males can become highly territorial with one another, especially in smaller tanks or when competing for mates. To mitigate aggression, it is best to keep a single male with several females or ensure a large, structurally complex environment where multiple males can establish their own territories. They are excellent community fish when housed with other small, peaceful species like smaller tetras, rasboras, and corydoras that will not outcompete them for food. Avoid housing them with boisterous or aggressive tank mates.

This species is an omnivore with a preference for carnivorous fare. In captivity, a high-quality diet is crucial for promoting health and breeding readiness. While they may accept flakes and small pellets, their diet should be regularly supplemented with live and frozen foods such as brine shrimp, daphnia, and bloodworms. They are moderately active and spend their time exploring the middle and bottom regions of the aquarium. With a lifespan that can reach up to several years, these fish represent a rewarding commitment for an aquarist who can provide a stable, well-maintained, and appropriately decorated environment.

Tateurndina ocellicauda is a member of the family Eleotridae, commonly known as sleeper gobies. This classification distinguishes it from true gobies (Gobiidae) by a distinct morphological trait: its pelvic fins are separate, whereas most true gobies possess pelvic fins that are fused to form a suction cup-like disc. Its species name, ocellicauda, is a Latin combination meaning 'eye-spot tail,' referring to the prominent dark spot at the base of its caudal fin.

This species exhibits noticeable sexual dimorphism, which becomes more pronounced with maturity. Males typically develop a prominent nuchal hump, a fatty deposit on the dorsal surface of the head, which is absent in females. Females, in contrast, tend to have a rounder, fuller abdomen, which becomes particularly conspicuous when they are gravid. The body shape is fusiform, streamlined for maneuverability in its native lentic (still water) habitats.

Ecologically, T. ocellicauda is endemic to the lowland freshwater systems of eastern Papua New Guinea. It occupies a niche as a micropredator, foraging in densely vegetated, slow-flowing streams and pools for small insects, larvae, and micro-crustaceans. Its low oxygen consumption and waste production indicate an efficient metabolism suited for its environment. According to the IUCN Red List of Threatened Species, Tateurndina ocellicauda is categorized as Least Concern (LC), reflecting a stable and widespread population within its native range with no immediate, significant threats to its survival.

Breeding Peacock Gudgeons is a moderately difficult but highly rewarding endeavor. Success begins with a well-conditioned and clearly sexed group of fish. Males can be identified by the prominent nuchal hump that develops on their head as they mature and their often more intense coloration. Females lack this hump and have a noticeably rounder body shape; when ready to spawn, their underside often takes on a distinct yellowish hue. For a breeding setup, a ratio of one male to two or more females is ideal to reduce courtship pressure on a single female.

A dedicated breeding aquarium is recommended. It should contain very gentle filtration, such as a sponge filter, to protect the eggs and fry. The key to triggering spawning is providing suitable caves. Small PVC pipes, terracotta pots, or purpose-built ceramic caves work perfectly. The male will select a cave, clean it, and begin an elaborate courtship display to entice a female inside. Once she is receptive, she will deposit her adhesive eggs onto the ceiling or walls of the cave.

After fertilization, the male will drive the female away and assume all parental duties. He will diligently guard the cave entrance and fan the eggs with his fins to provide oxygen and prevent fungal growth, a process that continues for several days until they hatch. Once the eggs hatch, it is advisable to remove the male, as his paternal instinct wanes and he may consume the fry. The newly hatched fry are minuscule and initially require microscopic foods such as infusoria or liquid fry food. After a few days, they can be transitioned to slightly larger foods like microworms and newly hatched brine shrimp. Maintaining pristine water quality through small, frequent water changes is critical for the survival and healthy development of the fry.