Rhinogobius formosanus – ~8 cm Formosa Brook Goby

The Formosa Brook Goby (Rhinogobius formosanus, Oshima 1919) is a sleek, freshwater goby native to Taiwan’s northern rivers. It typically grows to about 8 cm standard length, with males exhibiting vibrant orange-red facial markings, distinctive diagonal head lines, and striking blue-green sheen on their body scales. This species is known for its graceful movement, subtle aggression during dominance displays, and its adaptability—including landlocked populations, as well as amphidromous (migratory) life histories.

Care Instructions

• Tank Setup:

  • Preferred tank base: ~80 cm long (~60 liters) for a small group.

  • Substrate: Use fine sand, gravel, and rounded stones to recreate stream riverbeds. Incorporate driftwood and hideouts for shelter.  

• Water Conditions:

  • Temperature: 16–22 °C—cool to subtropical range suitable for biotope setups.

  • pH: Around 7.0–8.0.

  • Strong water flow and high oxygen levels are crucial; use powerheads or efficient filtration. Weekly 30–50% water changes help maintain pristine water quality.  Diet:

• • Omnivorous and not picky; readily accepts high-quality flakes, micro-pellets, and occasional frozen/live treats such as bloodworms, daphnia, or brine shrimp.

• Behavior & Social Structure:

  • Generally peaceful but males can be territorial—optimal stocking is one male per 60 cm with several females to reduce conflict.

  • Not overly aggressive toward other species, though dominance disputes may occur within same-gender groups.

• Breeding:

  • Males dig pits in substrate to breed and actively guard eggs.

  • Spawning has not been widely documented in captivity; captive breeding may require freshwater or brackish transitional setups.