Neon Green Rasbora

Microdevario kubotai

Animalia›Chordata›Actinopterygii›Cyprinidae

📍 Southeast Asia

Microdevario kubotai, the Neon Green Rasbora, is a tiny danionin from Thailand and Myanmar that glows with electric lime-green to yellow-green iridescence along its translucent body. At just 2–2.5 cm (0.8–1.0 in) it ranks among the smallest vertebrates kept in aquariums. It needs soft to moderately hard, slightly acidic water and does best in large groups of 15+ where the collective shimmering effect is most visible against dark substrates and fine-leaved plants.

Size1.5"

Min Tank10g

School6+

peaceful

Zonemid

Care Guide

Diet

Neon Green Rasboras are omnivores requiring a varied diet of micro-sized foods. Feed high-quality ultra-fine micro pellets as a staple, supplemented 2-3 times weekly with live or frozen micro worms and baby brine shrimp. Feed small amounts once daily, only what they can consume in 2-3 minutes, as their tiny mouths cannot process standard-sized foods.

Behavior

These are highly active, peaceful schooling fish that exhibit their most vibrant iridescent coloration and natural behavior only in groups of 15 or more. They spend most of their time in the mid-water column, darting and weaving through fine-leaved plants in coordinated groups. They are non-aggressive toward other peaceful species and show no territorial behavior.

Breeding

Breeding in captivity is extremely difficult and rarely achieved in home aquariums. They require pristine soft, acidic water (pH 5.5–6.5, 1–3 dGH), dense fine-leaved plants for egg scattering, and careful conditioning of breeding pairs. Fry are microscopic and require infusoria or liquid fry food for the first 2–3 weeks, making successful rearing a significant challenge.

Tank Mates

Ember Tetra

Similar size, peaceful temperament, and identical soft water preferences make them ideal companions

excellent

Red Cherry Shrimp

Peaceful invertebrates that thrive in soft, acidic water and won't prey on adult rasboras

excellent

Otocinclus

Small, peaceful algae eaters with compatible water parameter requirements

good

Dwarf Hairgrass

Fine-leaved plant that provides shelter and enhances the natural aesthetic for schooling behavior

excellent

Java Moss

Dense moss growth creates ideal habitat structure and spawning substrate for this species

excellent

Amano Shrimp

Larger shrimp species that coexist peacefully and help maintain plant health in soft-water setups

good

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

White spots on body and fins, rapid gill movement, lethargy, flashing against plants

Treatment

Raise temperature gradually to 28–29°C, perform daily 25% water changes, use ich medication (malachite green or formalin) at half-dose due to small size; improve water quality and reduce stocking density

Fin Rot

Symptoms

Frayed or deteriorating fin edges, discoloration at fin bases, progressive fin loss

Treatment

Perform immediate 50% water change, improve water quality (test ammonia/nitrite), treat with antibacterial medication or salt baths (1 tsp per gallon for 10 minutes daily); ensure excellent filtration

Bacterial Infection (Columnaris)

Symptoms

Cottony white growth on mouth or body, loss of appetite, isolation from school, rapid deterioration

Treatment

Isolate affected fish immediately, treat with antibiotic medication (tetracycline or oxytetracycline), maintain pristine water conditions, increase aeration; this is highly contagious and often fatal

Malnutrition/Stunting

Symptoms

Slow growth, faded coloration, lethargy, failure to school normally despite adequate tank size

Treatment

Increase feeding frequency to 3–4 times daily with varied micro foods (pellets, micro worms, brine shrimp); ensure diet includes vitamin-enriched foods and perform regular water changes to maintain water quality