Kubotai Rasbora Expert Care: Size, Tank Mates, Diet & Breeding

Kubotai rasbora care starts with a mature aquarium and a proper group. Plan for at least 10 fish. Give them a planted tank with a 60 × 30 cm footprint, then choose small companions that suit the same conditions.

Compare kubotai rasboras with other small species in the nano fish species guide.

The green colour gets your attention, but the tank dimensions deserve it too.

Kubotai rasbora care at a glance

Adult size About 2 cm Group 10 or more Minimum tank 60 × 30 cm Temperature 22–26 °C

These are practical care recommendations. They aren’t experimentally proven survival limits.

What is a kubotai rasbora?

The accepted scientific name is Microdevario kubotai. Kottelat and Witte originally described it as Microrasbora kubotai in 1999. Both names refer to the same fish.

So an older listing for microrasbora kubotai doesn’t identify another species. Check the full name when buying kubotai fish.

Appearance and adult size

The original description records greenish-yellow aquarium specimens with a glowing golden stripe along the side. The dorsal and anal fins are transparent.

Standard length leaves out the tail fin, which explains why size figures need some care.

A length of approximately 2.5 cm is given without specifying the measurement convention. For a clear size description, use about 2 cm excluding the tail. Don’t turn a measured specimen into a promise that every fish stops growing at exactly that length.

Minimum tank size and group size

My recommendation is to choose the tank by its footprint first because a volume label alone doesn’t tell you its length or width.

You can test your tank against the 60 × 30 cm base and a group of ten with our aquarium fish stock calculator.

At least 60 × 30 cm and lists approximately 54 litres, or 14 US gallons. A named keeper, Christian Splettstößer, independently recommends that footprint with a minimum height of 30 cm.

If you’re comparing tanks, take the dimensions with you. A tall tank and a longer tank can hold similar amounts of water.

Keep at least 10 together. Figures vary from 8 to 10 or more. Buy the aquarium for the group you intend to keep.

Temperature, pH and hardness

Use 22–26°C as the practical temperature range.

The published water guidance is pH 6.0–7.0 and 1–10 dGH. dGH measures general hardness. It isn’t a KH target.

Use those figures when planning your setup. Don’t read either endpoint as a tested boundary between safe and unsafe water.

Setting up the aquarium

Start with a mature tank. Provide dense planted areas and shaded cover, with moderate water movement. Leave room for the fish to swim. The current should support oxygenation without being severe.

Clean, oxygen-rich water also matters. Regular partial water changes belong in the maintenance routine.

My layout choice would be planted shelter around an open swimming area. Decide where the group will swim before filling every available space with decor.

What do kubotai rasboras eat?

Offer crushed flakes or micropellets that the fish can swallow. Small live or frozen foods can include baby brine shrimp, Cyclops and Daphnia.

Prepared food acceptance has also been documented in a laboratory study. The researchers maintained adult M. kubotai on tropical flakes and/or live Artemia.

But check what your own fish actually eat. Splettstößer reported that his newly acquired wild-caught fish initially struggled with some prepared foods. Live Artemia helped him improve their condition. They accepted more foods after settling in. That was one keeper’s experience with wild fish. It doesn’t establish a live-food requirement for every kubotai.

Watch a few mouthfuls during feeding. Picking food up and swallowing it are different things.

Choosing tank mates

Choose small, peaceful companions with matching care needs. Options include Boraras naevus, Trigonostigma espei and Pangio species. Treat these as candidates to check against your whole setup.

Each additional species needs its own space and suitable group. The kubotai tank recommendation doesn’t automatically leave room for another shoal.

If the fish you want have incompatible requirements, choose which species the aquarium will serve. A species tank is a straightforward option.

Can kubotai rasboras live with shrimp?

Adult shrimp coexistence has been reported. Splettstößer kept kubotai with Crystal Red shrimp in a mixed aquarium. He also said he couldn’t judge whether baby shrimp were being eaten.

That supports one successful setup. It doesn’t establish safety for every shrimp colony.

My advice is to keep fish separate if preserving shrimp offspring is your priority. Don’t build that plan around a promise of zero predation.

Male versus female

Mature females tend to be fuller-bodied. Males are described as more compact and more intensely coloured. For a detailed visual guide, see kubotai male vs female: how to tell them apart.

Use body shape as part of the comparison because colour alone won’t give you a dependable answer for every fish.

How long do kubotai rasboras live?

I couldn’t verify a typical aquarium lifespan from the reliable sources reviewed for this guide.

A precise lifespan number would need documented longevity records. None are available. Giving you an unsupported number would add certainty the evidence doesn’t have.

Breeding kubotai rasboras

Kubotai scatter eggs among vegetation and decor. Adults can eat eggs and larvae. A separate breeding aquarium with fine plants or spawning mops is recommended, followed by removal of the adults after spawning. For the full spawning setup, see our kubotai rasbora breeding guide.

The fry need very small initial foods. Introduce Artemia nauplii once they can accept them.

Exact hatch times remain insufficiently verified in the research behind this guide. Before setting up a breeding tank, decide how you’ll protect the offspring and feed the smallest fry.