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Blue axelrodi rasbora

Sundadanio axelrodi

Also known as Neon blue rasbora

FreshwaterFish

Blue axelrodi rasbora (Sundadanio axelrodi)

Care at a glance

Temperature
73–79°F
23–26°C
pH
4.0–6.5
Adult size
0.8 in
2 cm
Minimum tank
12 gal
45 L
Temperament
Peaceful
Social behavior
Shoaling
Swim level
Middle
Difficulty
Difficult
Breeding
Egg scatterer · Hard
Rarity
Common
Family
Cyprinidae
Origin
Southeast Asia: Greater Sunda Islands (Borneo and Sumatra), Indonesia; peat swamps and blackwater streams

Overview

The blue axelrodi rasbora is a tiny, timid shoaling fish for a dim blackwater tank. It is not a beginner fish, and it suits experienced keepers.

Did you know

The blue axelrodi rasbora's color is a fairly honest readout of how well the tank is dialed in. In soft, acidic blackwater the males light up with an electric blue stripe along the body. In harder or more alkaline water the color washes out, and the fish turn pale and stressed.

Caring for the blue axelrodi rasbora

Keep blue axelrodi rasboras as a colony of 20 to 30 or more, in a tank of at least 12 gal (45 L). They only show natural behavior and color in a real group, so plan the tank around the shoal rather than the single fish. Give them a dimly lit, densely planted tank with a soft sandy substrate and driftwood. Add a layer of oak, beech or Indian almond leaves, plus some peat fiber.

This demanding species needs stable water that is very soft and acidic, at 73 to 79°F (23 to 26°C). The pH can run from 4.0 to 6.5, though below 6 is better. Hard, alkaline tap water will not work for them. Feed small live and frozen foods such as baby brine shrimp and daphnia, since they often ignore dry food at first.

Blue axelrodi rasboras are peaceful and timid, and they stay in the middle of the water column. In a busy tank they are easily outcompeted and may simply stop feeding. Keep them with equally small, gentle tank mates, or on their own. They are sensitive to ich and to being exposed to air when netted, so move them gently in a cup of water.

They scatter their eggs among fine plants and mosses and give no parental care. Breeding them is hard.

Good to know

The blue axelrodi rasbora, Sundadanio axelrodi, is a nano fish in the family Cyprinidae. Some recent taxonomy places its genus in Danionidae instead.

In the wild

Blue axelrodi rasboras come from peat swamps and blackwater streams across the Greater Sunda Islands, on Borneo and Sumatra in Indonesia. These dark, tea-stained waters are very soft and acidic, shaded and full of leaf litter.

Weekly picks

Tank mates

The blue axelrodi rasbora is a peaceful, shoaling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a blue axelrodi rasbora need?

A blue axelrodi rasbora needs at least 12 gal (45 L). It spends most of its time in the middle.

What temperature and pH does a blue axelrodi rasbora need?

A blue axelrodi rasbora is comfortable at 73–79°F (23–26°C) with a pH of 4.0–6.5.

What does a blue axelrodi rasbora eat?

A blue axelrodi rasbora eats small live and frozen foods such as baby brine shrimp and daphnia. It often ignores dry food at first.

How big does a blue axelrodi rasbora get?

An adult blue axelrodi rasbora reaches about 0.8 in (2 cm).

Does a blue axelrodi rasbora need a group?

Yes. A blue axelrodi rasbora is a shoaling species and should be kept in a group, not singly.

How does a blue axelrodi rasbora breed?

Blue axelrodi rasboras scatter their eggs among fine plants and mosses, and the parents give no care. Breeding them is hard.

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