Coldwater Fish Guide | Discover Aquatics

Coldwater Fish Guide

All of these fish can live year-round without a heater (ideally 10–22°C / 50–72°F)

Goldfish

  • Common: 30-45cm, Fancy: 15-25cm
  • 10-20+ years
  • 200L+ for first fancy goldfish
  • 0-30°C (20°C ideal)
  • pH 6.5-8.5

Classic coldwater fish; extremely hardy once water quality is stable. Very high waste producers.

Shubunkin

  • 30-45cm
  • 10-20+ years
  • 1000L+ pond recommended
  • 0-30°C
  • pH 6.5-8.5

Calico-patterned single-tailed goldfish with blue background and red/orange/black spots.

White Cloud Mountain Minnow

  • 4cm
  • 3-5 years
  • 40L+ for school
  • 10-22°C
  • pH 6.0-8.0

Tiny, peaceful schooling fish with red nose and golden line. Ideal for unheated nano tanks.

Zebra Danio

  • 5-6cm
  • 3-5 years
  • 75L+ for school
  • 10-24°C
  • pH 6.5-7.5

Fast, active, striped schooling fish. Very hardy, great for beginners.

Hillstream Loach

  • 5-8cm
  • 5-8 years
  • 75L+ with strong current
  • 18-22°C max
  • pH 7.0-8.0

Flattened body, sucks on glass/rocks. Needs high oxygen and strong current.

Axolotl

  • 20-30cm
  • 10-15 years
  • 100L+ for one adult
  • 14-20°C (critical!)
  • pH 6.5-8.0

Neotenic salamander that keeps gills as adult. Regenerates limbs. Strictly coldwater.

Paradise Fish

  • 8-10cm
  • 6-8 years
  • 75L+ for one male
  • 16-22°C
  • pH 6.0-8.0

True coldwater gourami. Males very aggressive. Beautiful but territorial.

Weather Loach

  • 20-30cm
  • 7-10 years
  • 200L+ or pond
  • Tolerates near-freezing
  • pH 6.5-8.0

Eel-like, changes behavior before weather changes. Loves to burrow.

Japanese Rice Fish

  • 3-4cm
  • 3-4 years
  • 40L+ for school
  • 5-26°C
  • pH 6.5-8.0

Tiny fish with many color strains. Excellent for nano tanks or ponds. Easy to breed.