Neon Green Rasbora
Microdevario kubotai
Min Tank Size
40L
Adult Size
2 cm
Lifespan
3 years
School Size
8+
About
Native to small, slow-moving forest streams in Thailand and Myanmar, Microdevario kubotai is one of those fish that genuinely stops people mid-scroll. That vivid lime-green body, almost neon in quality, looks unreal under a well-planted tank's lighting. Adults rarely exceed 2 cm, placing them firmly in micro fish territory alongside species like Boraras and Sundadanio.
Water quality matters more than most beginners expect with this species. They come from soft, slightly acidic blackwater environments, so hard, alkaline tap water will suppress their color and shorten their lives. Aim for soft to moderately soft water with a pH in the 6.0 to 7.0 range for the best results. Temperature should stay stable between 22 and 27°C. Tannin-stained water from driftwood or Indian almond leaves really brings out that electric green against a dark substrate.
Feeding is straightforward since they'll accept most small prepared foods, but their tiny mouths mean standard community flakes are often too large. Crushed micro pellets, baby brine shrimp, and daphnia all work well. They're active and pick constantly throughout the mid and upper water column, so feeding little and often suits them better than large daily portions.
In terms of temperament, these fish couldn't be more peaceful. They pose zero threat to tankmates and spend their days darting around in loose formation, occasionally flashing that green when the light catches them just right. A dark-substrate planted nano tank with gentle flow really is their ideal setting.
If you want to see how other hobbyists have set up tanks for this species, browse Shimmerscape's community builds for real inspiration.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Neon Green Rasbora together
Neon Green Rasbora are shoaling fish and need company of their own kind. Keep a group of at least 8. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
These fish are best paired with other nano or micro species that share similar water parameter needs. Boraras brigittae, Sundadanio axelrodi, and small Danio species make excellent companions. Dwarf shrimp like Neocaridina and Caridina are completely safe with them. Sparkling gouramis and smaller Corydoras pygmaeus work well on different levels of the tank. Avoid anything large enough to view them as food, since at 2 cm they're bite-sized to most medium or large fish. Slow-moving species like fancy bettas can technically share space but watch for stress responses from the betta's side.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The most common mistake is keeping too few of them. A group of four looks sad, moves awkwardly, and shows dull coloration. Eight is the real minimum for welfare and visual impact. Hard water is the other big failure point since many keepers don't check their tap water hardness before buying these. A simple GH test and some RO dilution or peat filtration can transform how they look and how long they live. Their tiny mouths also mean you genuinely need appropriately sized food, standard flakes just get ignored or can't even be eaten.
Behavior & Aggression
Microdevario kubotai shows no meaningful aggression toward any tankmate. There's no territory-guarding, no fin nipping, no chasing. The only intraspecies behavior worth mentioning is mild jostling within the school, which is completely normal. Keeping them in groups of 8 or more distributes this behavior and keeps individuals looking their best. Stress from undersized groups or aggressive tankmates can cause them to hide and lose color, but that's a reaction, not aggression on their part.
Things to Know
- Very small size makes them vulnerable to larger tankmates; choose carefully.
- Needs a tight-fitting lid, they can jump through small gaps.
- Small school sizes cause stress and washed-out coloration; keep 8 or more.
- Can be easily outcompeted for food by larger or faster fish.
- A large school (10+) is needed for them to feel secure.
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