White Cloud Mountain Minnows: The Unheated River Tank Fish

White Cloud Mountain minnows (Tanichthys albonubes) are one of the best fish for a cool, unheated river tank. They're small, colorful and active, and they come from mountain streams in southern China, so they're happy in water that would be too cold for most tropical fish. They're also tough enough for beginners.

Quick facts

• Size: about 1.5 inches.
• Temperature: cool water. Many keepers aim for the mid-60s to low 70s °F. They can handle cooler water, but don't do well in hot tanks.
• Lifespan: several years with good care.
• Group size: at least six; more is better.
• Temperament: peaceful.

Do they need a heater?

Often, no. In a house that stays in the mid to upper 60s, many White Cloud tanks run unheated. They actually do worse in warm tropical tanks kept near 80°F, where they tend to live shorter lives.

If your house gets cold in winter, or the tank sits near a drafty window, a small heater set low acts as insurance against sudden drops. See best aquarium thermometers.

Tank setup

• Tank size: a 10-gallon can work for a small group; 20 gallons or more gives a school room to swim and show off.
• Flow: moderate. They enjoy some current but not a blasting manifold. In a strong river tank, give them calmer areas.
• Substrate and decor: river stones, sand, plants, and driftwood. They look best against a dark background with plants.
• Lid: yes. They can jump.
• Water: clean, well-oxygenated, cycled. See how to cycle a new aquarium.

Food

White Clouds eat almost anything small:

• Quality flakes and micro pellets
• Frozen or live foods like brine shrimp and daphnia
• Crushed flakes for fry

Feed small amounts once or twice a day.

Tankmates

Good tankmates:

• Hillstream loaches (they like similar cool, oxygen-rich water)
• Small danios
• Cherry and Amano shrimp (adult shrimp)
• Nerite snails
• Some cool-water gobies

Avoid:

• Bettas and tropical fish that need warm water
• Large or aggressive fish that will eat them
• Fancy goldfish (temperature fits, but goldfish get big and messy)

Colors and breeding

Males are slimmer and more colorful, with brighter fins, especially when they display to each other. Females are rounder.

White Clouds breed easily. In a planted tank with moss, some fry often survive on their own. To raise more, move adults out after spawning, since they'll eat eggs and fry.

Common varieties

Besides the wild type, you'll see gold, long-fin and "meteor" varieties. Long-fin types do better in calmer water.

Why they're a great river tank fish

They're cheap, hardy, don't need a heater in most homes, and look great schooling in a current. For a cool-water river tank, they're hard to beat. See best fish for strong-current tanks for more ideas.

Photo: White Cloud Mountain minnow (Tanichthys albonubes) captive adult female_captive_adult_female.jpg) by Ethmostigmus, CC BY-SA 4.0.

Related: Ten Fish That Thrive Best In A River Tank Style Aquarium (Riparium)