Blue Hillstream Trout
Blue Hillstream Trout
Blue Hillstream Trout (Opsarius bernatziki) is a stunning and active cyprinid from the fast-flowing hill streams of Southeast Asia. The elongated, streamlined body displays vivid iridescent blue to blue-green scaling with a warm lateral line — a combination that earns the evocative 'hillstream trout' name. This is a fast, open-water schooling fish very different from the suction-cup hillstream loaches it shares its habitat with.
Feeding & Care Tip: Sera Vipan Tropical Flakes and Hikari Micro Pellets make excellent daily staples. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Bloodworms or Hikari Frozen or Freeze-Dried Baby Brine Shrimp. Feed in good flow — this active species feeds confidently in the water column.
Native to fast-flowing, clear, well-oxygenated hill streams of Thailand, Myanmar, and surrounding Southeast Asia. Inhabits the mid-water zone of rocky streams with good current — the same habitat as hillstream loaches but occupying the open water above rather than the rocky bottom.
Keep in groups of at least six. An active, fast-swimming schooling fish that needs a long tank with good flow and high oxygenation. Compatible with other fast-water species. Will outcompete slow-moving or timid fish at feeding time.
The Blue Hillstream Trout is a spectacular schooling fish for fast-water aquariums — its vivid blue iridescence, trout-like streamlined body, and constant energetic movement create one of the most dynamic aquarium displays available.
Care & Ideal Parameters
| Difficulty | Easy — Moderate |
| Temperament | Peaceful — active schooling |
| Typical Adult Size | 5.0 inches (12.5 cm) |
| Min. Group Size | 6 minimum |
| Ideal Temp | 68–79°F (20–26°C) |
| Ideal pH | 6.5–7.5 |
| Ideal GH | 4–15 dGH |
| Ideal KH | 2–8 dKH |
| Staple Food | Sera Vipan Tropical Flakes; Hikari Micro Pellets |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Bloodworms; Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Fast-flowing hill streams, Thailand, Myanmar, and surrounding Southeast Asia |
| Notes | Active open-water schooling fish — occupies different zone from hillstream loaches. Vivid blue-green iridescence. Fast water and high oxygenation important. Groups of 6+. |
