| 1. Conservation Status |
|---|
| Scientific Name | Sahyadria denisonii |
| Common Name | Denison Barb / Roseline Shark |
| Family | Cyprinidae |
| IUCN Status | Endangered (EN) |
| Distribution | Western Ghats, India — Achankovil, Pamba, Chaliyar, and Valapattanam river systems |
| Notes | Declines driven by over‑collection for the aquarium trade, habitat fragmentation, and hydrological alteration. Species is a priority for ex‑situ conservation breeding. |
| 2. Natural Habitat & Ecology |
|---|
| Habitat Type | Fast‑flowing hill streams; high‑gradient rheophilic environments |
| Water | pH 6.5–7.2; GH 4–10; dissolved oxygen often > 8 mg/L; temperature 22–26°C |
| Substrate | Rounded stones, gravel, coarse sand; submerged roots and leaf accumulations |
| Behaviour | Obligate shoaling species; rapid darting locomotion; peak activity at dawn; occupies mid‑water column |
| 3. Water Chemistry Requirements |
|---|
| Temperature | 22–26°C (optimal spawning at 23–24°C) |
| pH | 6.5–7.2 |
| Hardness | GH 4–10; KH 2–6 |
| Flow | Strong laminar flow; turnover 8–12× per hour |
| Oxygenation | High saturation essential; spray bars or powerheads recommended |
| Lighting | Moderate; prefers shaded or dappled light zones |
| 4. Social Structure & Behaviour |
|---|
| Group Dynamics | Spawns best in groups of 8–12 adults; strong shoaling reduces stress |
| Male Behaviour | Intensified red lateral stripe; parallel swimming; rapid circling displays |
| Female Behaviour | Deeper‑bodied; increased abdominal fullness pre‑spawn |
| Territoriality | Low; brief competitive bursts during spawning events |
| 5. Conditioning Protocol |
|---|
| Duration | 2–3 weeks of high‑quality feeding |
| Diet | Live daphnia, mosquito larvae, bloodworms; spirulina‑rich pellets; high carotenoid content improves colour and fertility |
| Environmental Stability | Strong flow, high oxygen, low organic load; stable temperature |
| Indicators | Males intensify colour; females show gonadal swelling and increased feeding |
| 6. Spawning Strategy |
|---|
| Method | Open/substrate egg‑scatterer; no parental care |
| Spawning Sites | Coarse gravel beds, fine‑leaved plants, high‑flow zones |
| Spawning Behaviour | Early‑morning spawning; rapid circling; adhesive eggs scattered into substrate interstices |
| Parental Care | None; adults must be removed immediately to prevent predation |
| 7. Spawning Triggers |
|---|
| Pre‑Trigger | High oxygenation; strong flow; stable temperature |
| Trigger Event | Large cool water change (20–30% at 2–4°C lower) |
| Additional Stimuli | Increased aeration; dawn light transition; elevated feeding the day before |
| 8. Eggs & Incubation |
|---|
| Clutch Size | 50–150 eggs |
| Egg Type | Adhesive; settle between gravel particles |
| Incubation | 24–36 hours at 24–26°C |
| Notes | Eggs highly sensitive to sedimentation; require high oxygen and clean flow |
| 9. Larval Development |
|---|
| Day 0–2 | Yolk sac absorption; limited mobility; remain near substrate |
| Day 3–4 | Free‑swimming; swim bladder inflation; begin exogenous feeding |
| Day 5–14 | Require microscopic foods; rapid growth with high oxygen availability |
| Week 2–4 | Colouration begins forming; shoaling behaviour develops; increased flow tolerated |
| 10. First Foods & Feeding Schedule |
|---|
| Stage 1 (Day 3–7) | Rotifers, microworms |
| Stage 2 (Day 5–14) | Small‑strain Artemia, micro‑foods |
| Stage 3 (Week 2–4) | Artemia, powdered fry diets |
| Stage 4 (4+ weeks) | Live foods; fine pellets; increased flow to strengthen musculature |
