Rainbow Shiner (1.5”)

Notropis chrosomus 

Maximum Size and Lifespan

• Size: Up to 2.5-3" in length.

• Lifespan: Typically 2–3 years, though with excellent care they may reach 4 years in captivity.

Recommended Aquarium Size, Water Changes, and Care

• Tank Size: A 10 gallon tank is the minimum for a small group, but 15+ gallons is strongly recommended since these are active schooling fish that require high oxygen levels.

• Water Parameters:

  • Temperature: 60–75°F (15–24°C), cooler side preferred. They can tolerate higher temperatures up to 80F with caution

  • pH: 6.5–7.5.
    

• Water Flow & Oxygenation: They thrive in well-oxygenated aquariums with moderate to strong flow, mimicking their stream habitats.

• Water Changes: Weekly 30–40% water changes are ideal to keep water clean and oxygen-rich.

• Care Notes: Provide smooth rocks, driftwood, and open swimming areas. A secure lid is necessary as rainbow shiners can jump.

Tankmates

• Best in schools of at least 8–10 individuals to reduce stress and encourage natural coloration.

• Peaceful, compatible with other cool-water community fish such as:

  • White Cloud Mountain Minnows, Hillstream Loaches, Smaller danios and rasboras, and corydoras

• Avoid keeping with aggressive or much larger fish that may harass or outcompete them.

Diet

• Omnivorous and opportunistic.

• In captivity, feed a varied diet of:

  • High-quality flake and micro pellets

  • Frozen bloodworms and brine shrimp

  • Spirulina based pellets and flakes

• 1-2 feedings per day

Breeding

• Breeding Behavior: Seasonal spawners in nature, most active in spring and early summer when water temperatures rise.

• Courtship: Males display their brightest colors and chase females.

• Spawning: Egg scatterers; no parental care. Eggs often deposited among gravel or plant roots.

• Captive Breeding:

  • Best achieved in a species-only tank with fine gravel or spawning mops.

  • Maintain slightly cooler water, then gradually increase temperature to 70–72°F (21–22°C) to trigger spawning.

  • Adults may consume eggs, so use spawning traps or remove parents post-spawn.

  • Eggs hatch in 3–5 days, fry feed initially on infusoria and then baby brine shrimp.

Natural Environment

Rainbow Shiners are native to clear, cool, fast-flowing streams and rivers in the southeastern United States, especially in Alabama, Georgia, and Tennessee. They inhabit rocky riffles and runs where water is well-oxygenated and temperatures remain lower than in stagnant waters. In the wild, they feed on small invertebrates, algae, and organic matter.

The Rainbow Shiner (Notropis chrosomus) is a small, short-lived, but spectacular schooling fish best suited to well-oxygenated aquariums with moderate flow and cooler temperatures. They thrive in groups, accept a wide diet, and display breathtaking colors during spawning. With proper care, they can be successfully bred in captivity, making them a rewarding species for aquarists who appreciate both beauty and natural behaviors.