Red Rainbowfish (Glossolepis incisus) — 5–7 cm (Sub-adult Size)

Overview & Natural History

• Commonly called the Red Rainbowfish or Salmon-Red Rainbowfish.

• Native exclusively to Lake Sentani, Papua New Guinea .

• Males develop a vivid salmon-red coloration and pronounced arched backs; females and juveniles remain olive to yellow-brown with silvery sheen 

• Typically reach around 12 cm, though males may grow up to 15 cm .

• This species is endangered in the wild, emphasizing the importance of choosing captive-bred sources 

Care Instructions (8–9 cm Specimens)

• Tank Size: Minimum 55–75 gallons (208–285 L) for a shoal of 6–8 individuals .

• Water Conditions:

  • Temperature: 72–82°F (22–28 °C) 

  • pH: 7.0–8.0, slightly alkaline preferred 

  • Hardness: 9–19 dGH (moderately hard) 

• Aquarium Setup:
  Planted with dense vegetation, a dark substrate to enhance their coloration, and open zones for swimming. Gentle water movement is ideal 

• Diet: Omnivorous—provide high-quality flakes/pellets plus live or frozen protein sources like brine shrimp and bloodworms to enhance color 

• Social Behavior:
  Active schooling fish; keep in groups of 6–10 (with more females than males) to reduce stress and encourage vibrant coloration—especially in males 

• Breeding: Egg scatterer. Use fine-leaved plants or spawning mops. Fry hatch in about a week and thrive with gentle care and small live foods .

• Lifespan: Typically 5–8 years with proper care