Peacock gudgeons, Tateurndina ocellicauda, are small freshwater sleepers from Papua New Guinea. They can suit a quiet planted aquarium, but need sheltered territories and food that reaches them. They are not suitable companions for every fish described as “peaceful.”
Size, sexing and aquarium layout
Common aquarium adults are around 5–7 cm. Males usually develop a bulkier head and may be larger, while females often show a yellow belly. Use several mature features together rather than treating one fin marking as an infallible sex test.
For a small community or several gudgeons, a 20-gallon long aquarium or larger offers a useful starting footprint. A dedicated pair can be housed differently, but other bottom-dwellers, rival males and breeding caves all require space. Provide multiple refuges with broken sight lines and keep a separation option available.
Use smooth substrate, plants and secure wood or caves. Java fern and Anubias can provide cover without demanding intense light. Fit a cover without escape gaps. Plants do not replace filtration or oxygenation, especially at night.
Water conditions
The species profile gives 22–26°C, pH 6.5–7.5 and soft to moderately mineralized water. Keep conditions stable and match the source stock. Driftwood tannins do not reliably remove the minerals measured as general hardness.
Complete the nitrogen cycle, maintain zero ammonia and nitrite and monitor nitrate. Use gentle circulation with surface movement rather than blasting the fish with a strong outlet. Remove debris and make regular partial water changes.
Feeding: confirm each fish eats
Offer small suitable frozen or live aquatic foods, such as Artemia, Daphnia or appropriately sized insect larvae, alongside an accepted complete micro-pellet. Confirm food acceptance before purchase. Captive-bred origin does not guarantee that every individual immediately eats any flake offered.
Deliver modest portions near their feeding area and watch them swallow. A feeding baster can help when other fish intercept the meal. Do not solve missed meals by scattering excessive food over the whole tank; leftovers add waste without ensuring that the gudgeon eats.
Tank mates and social behavior
Calm, appropriately sized schooling fish such as harlequin rasboras can be candidates when water conditions and space match. Avoid fin-nippers, large predators and territorial bottom-dwellers that can claim every refuge.
Betta compatibility depends on the individual and layout; it is not guaranteed by using a larger tank. Warm-water discus setups are not the default match for gudgeons. Shrimplets and tiny fry may be eaten, and adult ornamental shrimp should not be promised complete safety.
A small group can show interesting social behavior, but rival males still need space. Separate fish if one is repeatedly chased, cannot feed or remains trapped in cover. Displays do not prove that all disputes are harmless.
Cave spawning and fry
Provide small smooth caves or suitable tubing. The male attracts a female to a spawning site and tends the attached eggs. Walter Hilgner’s firsthand breeding account describes hatching after about nine days, with free-swimming fry the following day. Timing varies with conditions; observe development rather than using a rigid calendar.
Prepare an established fry setup with gentle filtration and protected intake. Very small first foods such as cultured infusoria can bridge the transition to newly hatched Artemia once the fry can take them. Check feeding directly and keep water clean. Other community fish may eat the young, so do not assume the cave alone protects a brood.
