Freshwater Fish
Neon Green Rasbora
A tiny schooling fish with a vivid neon lime-green body that fluoresces under aquarium lighting. One of the few freshwater fish whose colour intensity genuinely rivals marine species, and an outstanding companion for shrimp.
Neon Green Rasboras (Microdevario kubotai), also known as Kubotai Rasboras and Green Rasboras, are a tiny schooling fish from the clear forest streams and shallow tributaries of western Thailand and Myanmar. Adults reach approximately 2cm in length, making them one of the smallest schooling fish in the hobby, and their defining characteristic is a vivid neon lime-green colouration that fluoresces intensely under quality aquarium lighting. The colour intensity is genuinely remarkable for a freshwater species, rivalling many marine fish, and in a school of 10 or more moving through a planted tank the collective green shimmer creates one of the most striking visual effects achievable in a nano aquarium. They are peaceful, tight-schooling, and exceptionally compatible with shrimp. Note that the invoice designation Rasbora kubotai is an older name for this species; the current accepted scientific name is Microdevario kubotai. Keep in schools of 8 or more in a densely planted tank with dark substrate for the most vivid colour expression.
6.0–7.5pH
2–12GH (dGH)
72–79°FTemperature
0.8 inMax Size
Appearance & Schooling
Neon Green That Actually Glows
Vivid neon lime-green body with a fluorescent quality under aquarium LEDs. The green colouration of M. kubotai is unusual among freshwater fish in both hue and intensity. Under quality aquarium lighting the green appears to fluoresce rather than simply reflect, producing a glow effect that is genuinely rare in freshwater species. A vivid neon green-yellow lateral stripe runs along the body and is the most intensely coloured element. Some specimens display a subtle blue shimmer alongside the green under certain lighting conditions.
Dark substrate dramatically enhances the fluorescent colouration. This is the single most impactful setup decision for displaying Neon Green Rasboras. Against dark substrate such as aquasoil or black sand the neon green reads at maximum intensity. Against pale substrate the colour washes out significantly and the fluorescent quality is largely lost. Red aquarium plants provide an additional complementary contrast that makes the green appear even more vivid.
Tight schooling behaviour -- keep in groups of 8 minimum, 15 or more preferred. Neon Green Rasboras school more tightly than most nano fish, moving as a coordinated group through the upper and middle water column. In groups below 8 they become nervous, hide frequently, and show washed-out colour. A school of 15 or more produces the dense green shimmer effect the species is known for and gives the fish the confidence to occupy open water rather than sheltering in plant cover.
Males more intensely coloured than females, particularly when competing for attention. Mature males are slimmer and display noticeably more intense neon green colouration, especially during competitive displaying. Well-conditioned females become fuller-bodied as they develop eggs. A mixed-sex group produces the most active displaying and the best sustained colour from the males.
Requires stable, well-maintained water -- not the hardiest nano fish. Neon Green Rasboras are less forgiving of poor water quality and parameter swings than hardier species like White Cloud Mountain Minnows. They require a mature, cycled, stable tank with consistent small partial water changes. This is not a fish for a new or cycling aquarium. In stable conditions they are straightforward to keep long-term.
Moderate flow and good oxygenation, with floating plants to diffuse light. They come from clear flowing streams and appreciate moderate water movement for oxygenation, though not harsh current. Floating plants diffuse overhead lighting and give the fish confidence to occupy open water. Dense stem plants and mosses around the perimeter with open central swimming space is the ideal layout.
Shrimp Compatibility
Exceptional Shrimp Companion
Tiny mouth -- adult Neocaridina and Caridina shrimp are completely safe. At under an inch with a proportionally tiny mouth, M. kubotai poses no threat to adult shrimp of any species. Only the very smallest newly hatched shrimplets are at any risk, and in a densely planted tank with moss cover shrimplet survival rates alongside Neon Green Rasboras are high. They are specifically noted for exceptional compatibility with shrimp and other nano species.
Upper and mid-water schooling means minimal interaction with substrate-level shrimp. Neon Green Rasboras occupy the upper portion of the water column and school in open water. Shrimp work the substrate, hardscape, and plant surfaces below. The vertical separation between the two species means they essentially share the tank without competing for space or resources at any point.
Parameter range overlaps well with both Neocaridina and soft-water Caridina setups. At pH 6.0 to 7.5 and moderate hardness, Neon Green Rasboras sit comfortably within the Neocaridina range and at the upper end of the Caridina range. A soft-water Neocaridina tank at pH 7.0 is ideal for both species simultaneously.
Pairs exceptionally well with Chili Rasboras for a red and green display. The vivid green of M. kubotai and the scarlet red of Chili Rasboras are visually opposite and create a dazzling effect when both species are schooled in the same densely planted tank. Both share similar care requirements, similar size, and identical shrimp compatibility.
Keeper's NoteA school of 15 Neon Green Rasboras over dark aquasoil with red stem plants in the background and a colony of Fire Red Cherry shrimp working the substrate below is one of the most colour-saturated nano tank displays achievable in freshwater. The neon green of the fish against the dark substrate, the red plants providing complementary contrast, and the red shrimp echoing the plant colour at the substrate level create a display where every element reinforces every other. Give the tank three months to mature before adding the Rasboras, keep the water stable, and this is a setup that only improves over time.
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