How to Breed Lambchop Rasboras: Espei Spawning Guide
Lambchop rasboras — Trigonostigma espei — are among the prettiest nano fish in the hobby, yet surprisingly few keepers attempt to breed them. This breed lambchop rasbora guide from Gensou Aquascaping at 5 Everton Park, Singapore, breaks down the process into manageable steps. Unlike their close relative the harlequin rasbora, espei spawning requires slightly softer, more acidic conditions. Once you crack the formula, watching these copper-and-black gems deposit eggs under broad leaves is immensely satisfying.
Understanding Espei Spawning Behaviour
In the wild, T. espei spawns during the rainy season when water softens and temperatures drop slightly. They are egg scatterers with a twist — females prefer to deposit adhesive eggs on the underside of broad-leaved plants. This upside-down spawning posture distinguishes them from most small cyprinids. Males court females with vigorous lateral displays, intensifying their copper colouration. Spawning typically occurs in the early morning hours when light levels are low.
Conditioning the Breeding Pair
Separate males and females for two weeks before the breeding attempt. Feed heavily with live or frozen daphnia, grindal worms, and baby brine shrimp — high-protein foods trigger egg production in females. A well-conditioned female develops a noticeably rounded belly. Select the most intensely coloured male; strong pigmentation usually indicates robust health. Aim for a ratio of two males to three females for the best results, though a single pair can work in a small breeding tank.
Setting Up the Breeding Tank
A 20-30 litre tank is sufficient. Keep it bare-bottom or use a thin layer of fine sand. Add several Cryptocoryne species or Anubias with broad leaves — these provide the spawning surfaces the fish require. A clump of Java moss on the substrate catches any eggs that fall. Use a sponge filter set to a gentle flow. Dim the lighting or cover three sides of the tank to reduce stress. Fill with RO water remineralised to GH 2-3 and KH 1-2, targeting a pH of 5.5-6.5 and a temperature of 26°C.
Triggering the Spawn
Introduce the conditioned group in the evening. A small water change with slightly cooler water — about 1-2°C below tank temperature — simulates the rain trigger. Lower the water level to around 15 cm to concentrate pheromones. By the following morning, you should observe males displaying alongside females near the undersides of leaves. The female flips upside down to press eggs onto the leaf surface while the male fertilises them. Each spawning event produces 30-80 eggs over several hours.
Egg Care and Hatching
Remove the adults immediately after spawning — they will eat the eggs given the chance. Eggs are tiny, transparent, and adhesive, visible as small dots on the leaf undersides. Add a few drops of methylene blue to prevent fungal growth. Maintain the water temperature at 26-27°C. Hatching occurs within 24-36 hours, and the fry become free-swimming after another 3-4 days. Keep the tank dark during this period; bright light can increase egg mortality in soft-water species.
Raising the Fry
Free-swimming fry are minuscule, roughly 3 mm long. Start with infusoria or commercially available liquid fry food for the first five days. Transition to freshly hatched baby brine shrimp (Artemia nauplii) from day six onward. Feed small amounts three to four times daily, siphoning uneaten food carefully with airline tubing. Growth is steady but not fast — expect the lambchop markings to become visible at around four weeks. At the six-week mark, fry can join a gentle community tank.
Common Breeding Challenges
Eggs turning white within 12 hours indicates infertility or fungal infection. Ensure your male is mature — at least 8-10 months old — and that water parameters are stable. Singapore’s tap water, while soft, still needs adjustment via RO blending for the very low hardness espei prefer. Another common mistake is leaving the light on too long during spawning; ambient room light or a weak LED on a timer set to six hours works well. Patience is essential — some pairs need two or three attempts before a successful spawn.
Rewarding Efforts
Successfully breeding Trigonostigma espei is a genuine accomplishment that deepens your understanding of soft-water fishkeeping. Surplus fry are always in demand locally — juvenile lambchop rasboras sell for $1-2 each on Carousell. For hobbyists in Singapore looking to advance their skills, Gensou Aquascaping offers the knowledge to help you breed lambchop rasboras and other challenging nano species with confidence.
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emilynakatani
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