Easy

Rainbowfish

By The Aquarium Calculators Editorial Team ·

Melanotaeniidae

Complete Rainbowfish care guide covering omnivore diet requirements, peaceful temperament, minimum 20 Gallons tank setup, and compatible freshwater tankmates. Difficulty: Easy.

Rainbowfish

Quick Answer

Rainbowfish (Melanotaeniidae) is a captivating and highly sought-after freshwater species. It requires a minimum 20 Gallons aquarium with a pH of 6.5 - 7.5 and temperature range of 22-26°C. This omnivore occupies the middle zone and makes an excellent addition to community setups.

Intro

Rainbowfish (Melanotaeniidae) is a captivating and highly sought-after freshwater species. Known for their peaceful nature and distinct appearance, they occupy the middle levels of the aquarium and bring dynamic energy to any setup.

Setup

Rainbowfish requires a stable, well-filtered aquarium of at least 20 gallons. They thrive best with moderate water movement and a reliable heater to maintain temperatures around 22-26°C. Ensure pH levels remain consistent between 6.5 - 7.5 to prevent stress and support long-term health.

Feeding

As a omnivore, the Rainbowfish is not a picky eater. They should be fed a high-quality base of flakes, sinking pellets, or wafers. Periodic supplementation with frozen or live foods, such as bloodworms or brine shrimp, will boost their health and colors.

Compatibility

Rainbowfish has a peaceful temperament. They are schooling fish and MUST be kept in a group of at least 6 individuals to exhibit natural schooling behavior and reduce stress. Avoid placing them with aggressive species or tankmates they are listed as incompatible with, such as: None.

Fish Compatibility Calculator

Enter your details below for an instant recommendation.

Recommended Output

Pair status badge

--

Pair status desc

--

Temp pct val

--

Temp summary text

--

Ph pct val

--

Ph summary text

--

Space val

--

Space summary text

--

Layer emoji

--

Layer status text

--

Layer badge

--

Profile temp badge

--

Perfect list

--

Caution list

--

Incompatible list

--

Profile emoji

--

Profile name

--

Profile sci

--

Profile zone

--

Profile mintank

--

Profile temp

--

Profile ph

--

Profile note

--

Perfect count

--

Caution count

--

Incompatible count

--

Tank Position
Middle
Water Temp
22-26°C
Adult Size
See profile
Water pH
6.5 - 7.5

Species Characteristics

Adult Size
Lifespan
Growth Rate
moderate
Tank Compatibility
Community compatible
Indoor Aquarium
Yes

Water Parameters

Water Temperature
Humidity
Water pH

Tank Lighting

Tank Lighting
Standard lighting
Light Hours
N/A
Intensity
moderate

Feeding & Diet

Diet Type
Diet: Omnivore
Feeding Schedule
N/A
Live Food Options
N/A

Frequently Asked Questions

How many Rainbowfish should be kept together?
Maintain a minimum school of 6 to 8 individuals in a tank of at least 40 gallons (150 liters) with a footprint of 48x15 inches (120x38 cm). Rainbowfish (Melanotaeniidae family) are schooling fish that need the company of their own kind to feel safe and active. Groups under 5 cause faded colors and stress. A school of 10+ displays optimal iridescent coloration. Maintain a 1 male to 2 female ratio. Provide open swimming lanes and dark substrate. Tank length must exceed 4 feet (120 cm).
What are the exact water parameters for Rainbowfish?
Target pH 6.5 - 7.5, General Hardness 8 - 15 dGH, Carbonate Hardness 6 - 12 dKH, Total Dissolved Solids 150 - 400 ppm, Electrical Conductivity 300 - 800 μS/cm, and temperature 72°F - 80°F (22°C - 27°C). They prefer hard, alkaline water; soft water (dGH <4) causes clamped fins. Maintain nitrates below 15 ppm with weekly 25% water changes. Use a canister filter with high flow (10x turnover). Provide open swimming areas. Hardness below 5 dGH reduces coloration.
What is the dietary and medication protocol for Rainbowfish?
They are omnivores requiring 45% protein, 12% fat, 43% plant matter. Feed high-quality flake or pellet, supplemented with frozen brine shrimp, daphnia, mysis, and bloodworms twice daily. Offer spirulina flakes and blanched peas weekly. Medication alert: Tolerate copper (0.2 mg/L) but sensitive to formalin. Praziquantel is safe. Salt baths up to 5 ppt treat external parasites. Quarantine with methylene blue for 7 days. They are susceptible to ich; treat with malachite green at half-dose.
How to breed Rainbowfish in captivity?
Select 10-12 mature fish (1 male:2 female) and condition with live blackworms and brine shrimp for 3 weeks. Set up a 20-gallon (75 liter) breeding tank with 8 inches (20 cm) of water (pH 7.0, dGH 8, 75°F/24°C), a spawning mop, and java moss. Spawning occurs daily at dawn; females release 50-200 adhesive eggs daily over several days. Remove parents every 2 days. Eggs hatch in 7-10 days at 72°F (22°C). Fry feed on infusoria for 3 days, then microworms, then baby brine shrimp. Grow-out requires frequent water changes.