Parosphromenus linkei — Breeding & Rearing
Species Breeding & Rearing Profile
| Category | Details |
|---|---|
| Taxonomy |
Order: Anabantiformes Family: Osphronemidae Genus: Parosphromenus Species: Parosphromenus linkei (Kottelat, 1990) |
| Natural Habitat |
Peat swamp forest streams in Borneo (Kalimantan). Extremely soft, acidic blackwater: pH 3.5–5.0, conductivity often <30 µS/cm. Shallow, shaded leaf‑litter channels with root tangles and minimal flow. Hypoxic microhabitats under dense canopy; very low light penetration. |
| Adult Morphology |
Small licorice gourami; males ~30–35 mm SL, females slightly smaller. Males: dark body with iridescent blue/green and red patterning in unpaired fins, pointed dorsal and anal fins. Females: more subdued brown‑grey, rounder belly, shorter fins, visible ovipositor when ripe. Labyrinth organ present; adapted to oxygen‑poor environments. |
| Breeding Triggers |
Gradual reduction of conductivity to <40 µS/cm using RO/rainwater. pH 3.5–4.8 via heavy botanical loading (catappa, oak, peat). Temperature 24–26°C with minimal daily fluctuation. Very dim lighting and dense cover (leaf litter, roots, caves). 10–14 days of live‑food conditioning (small insect larvae, Artemia, grindal). |
| Courtship Behaviour |
Male establishes a small territory around a cave or leaf tube. Courtship displays include lateral showing, fin flaring, and colour intensification. Female is enticed into the cave; pair performs repeated embraces inside the shelter. Aggression is low but males may chase rival males from the spawning site. |
| Spawning Method |
Cave‑spawning bubble‑nest species. Male constructs a small bubble nest on the ceiling of a narrow cavity (film canister, leaf tube, small cave). Eggs are attached to the roof; male remains in or near the cave to guard and tend the clutch. Female is usually driven away after spawning. |
| Egg Development |
Clutch size typically 10–40 eggs depending on female condition. Incubation 24–36 hours at 25–26°C. Larvae remain attached to the cave roof or nest for a further 3–4 days until free‑swimming. Male collects fallen eggs/larvae and returns them to the nest. Eggs are highly fungus‑prone outside very soft, acidic water. |
| Larval Stage |
Newly hatched larvae are non‑motile and rely on yolk reserves. First feeding window opens around day 4–5 post‑hatch when fry become free‑swimming. Mouth gape extremely small; requires micro‑foods (infusoria, rotifers, paramecium). Sensitive to current and bright light; best kept in very still, dim conditions. |
| Fry Rearing |
Initial diet: infusoria, rotifers, paramecium, cultured micro‑plankton. Artemia nauplii and microworms introduced cautiously from day 10–14, depending on growth. Maintain pH <5.0 and conductivity <50 µS/cm during first month. Daily 5–10% drip water changes with pre‑conditioned, temperature‑matched blackwater. No mechanical filtration or only very gentle sponge filtration. |
| Juvenile Development |
Pigmentation and fin patterning begin to appear at 6–8 weeks. Sexing possible at ~10–12 weeks as males develop more intense colours and fin extension. Juveniles remain shy and require dense cover and low light. Mild intraspecific aggression; small groups can be reared together with ample space and structure. |
| Genetic Considerations |
Maintain locality‑pure lines; avoid mixing with other Parosphromenus species or forms. Outcross within the same locality line every 3–4 generations to reduce inbreeding. Monitor for loss of wild‑type colour and behaviour under captive selection. Record provenance (collection code, locality, year) where available. |
| Health & Disease |
Highly sensitive to elevated TDS, pH >6.0, and bacterial blooms. Blackwater conditions (humic substances, low pH) help suppress many pathogens. Avoid strong medications; use targeted, low‑dose treatments only when essential. Stable, clean, low‑nutrient water is more important than heavy filtration. |
| Production Scaling |
Low to moderate fecundity; not suited to mass‑production. Best managed as multiple small breeding pairs or trios in species‑only setups. Primary value is conservation and specialist hobbyist demand rather than volume trade. Careful record‑keeping and distribution to responsible keepers recommended. |
Rearing Protocol Summary
Conditioning Adults
- Small live foods (Daphnia, mosquito larvae, grindal worms, Artemia)
- TDS <50 ppm, pH 4.0–5.0
- Heavy botanicals and leaf litter
- Very dim lighting and minimal disturbance
Spawning Setup
- 10–20 L tank, dark background
- Multiple small caves (film canisters, leaf tubes, narrow ceramic caves)
- Water depth 10–15 cm
- Gentle or no filtration; air‑driven sponge at very low flow if used
Fry First Foods
- Infusoria
- Rotifers
- Paramecium
- Transition to Artemia nauplii and microworms after sufficient growth
Growth Management
- Daily or near‑daily micro water changes (5–10%)
- Maintain stable blackwater conditions
- Provide fine‑structured cover (mosses, roots, leaf litter)
- Separate sexes or reduce density as aggression increases
Notes for Keepers
Parosphromenus linkei is a specialist blackwater labyrinth fish requiring very soft, acidic, tannin‑rich water, low light, and cave spawning structures. It is best maintained and bred as part of a conservation‑minded programme with careful attention to water chemistry and line purity.
