Rainbowfish (Melanotaenia and related species) is a beginner-level freshwater fish that needs at least 30 gallons and 72-80°F. Active, colorful schooling fish that need long tanks and hard, alkaline water.

Care facts at a glance

Scientific nameMelanotaenia and related species
FamilyMelanotaeniidae
OriginAustralia and New Guinea
Adult size4 in
Minimum tank30 gallons
Temperature72-80°F
pH7.0-8.0
TemperamentPeaceful, active
Social behaviorSchooling, keep 6+
Swim levelUpper to mid
DifficultyBeginner
DietOmnivore: flakes, pellets, frozen foods
Typical lifespan5-8 years

Quick tips

  • Keep a group of six or more.
  • Give it room to swim.
  • Prefers harder water.

San Diego water

Naturally suited to San Diego's hard, alkaline tap water once it is dechlorinated (the city uses chloramine, so use a conditioner that handles it). Learn the numbers in our San Diego tap water guide.

Before you buy

Make sure your tank is cycled (how to cycle a tank), check your numbers with the water testing guide, and use the compatibility guide to check tankmates. These are general ranges; individual fish and local water vary.

Find it at Pet Zone

Pet Zone Tropical Fish is a San Diego aquarium store with two locations. Stock changes daily, so call ahead if you are after a specific species or plant. Shop online at petzonesd.com.

Pet Zone Convoy

4160 Convoy St, San Diego, CA 92111
(858) 987-0309
Open daily, 10am-6pm

Aquascaping, planted tanks

Pet Zone Mid-City

4266 University Ave, San Diego, CA 92105
(619) 283-1812
Closed Monday; Tue-Fri 10:30am-6pm, Sat 11am-6pm, Sun 11am-4pm

Monster fish, koi