Yellowtail Rasbora (Rasbora tornieri)

Yellowtail Rasboras are a peaceful and timid species making them excellent members of a well-researched community aquarium. However, these fish are intolerant to the buildup of organic wastes and require pristine water at all times to thrive, meaning a strict maintenance regime is essential. Therefore these fish are not suitable for a beginner aquarist.

Yellowtail Rasboras are a schooling species in nature, so ideally, you should purchase and keep these Rasboras in groups of at least six individuals. Maintaining these fish in good numbers will not only make the fish less nervous but will result in a more natural-looking arrangement. At the same time, males will exhibit some exciting behaviours as they compete with each other for female attention.

You can keep these Rasboras in a species-only aquarium or house them with similarly sized species with the same peaceful temperament. However, it would be best if you did not keep these fish with much larger, more boisterous or aggressive species.

Yellowtail Rasboras can grow to 15 cm in length; therefore, it is recommended that you have an aquarium of at least 225 litres to maintain a shoal of these fish. Also, make sure you have a tight-fitting lid, as these fish may jump if they feel threatened.

Yellowtail Rasboras will do better in a heavily planted aquarium or a set-up designed to mirror a flowing river with a substrate of different sized gravel and stones, some large smooth rocks and medium water movement. You can also add some driftwood alongside some hardy aquatic plants.

Yellowtail Rasboras have a silvery body with a thick, dark brown, prominent midlateral stripe extending from the operculum to the caudal fin base. Above that, they have a second light yellowish coloured stripe. Finally, they have a bright yellow caudal fin that is edged with black.

Photos of the Yellowtail Rasbora

Natural Habitat

Yellowtail Rasboras occur in Indonesia, Malaysia, Borneo, Sumatra, Indochina, and Thailand, as well as the Belait River Basin in Brunei Darussalam to the Sambas drainage in West Kalimantan in Southeast Asia.

Yellowtail Rasboras can be found in various habitats, including flowing streams as well as more sluggish blackwaters associated with areas of old peat swamp forests that are typically covered in fallen leaves, twigs and branches.

They also inhabit permanent bodies of water, including pools, backwaters, canals, ditches and reservoirs, and are also known to move into flooded areas during the wet season.

What to feed the Yellowtail Rasbora

In the aquarium, Yellowtail Rasboras will accept good-quality dried foods of a suitable size. However, it would be best if you did not feed them this solely; instead, you must also offer them daily helpings of small frozen and live fares such as artemia, daphnia, bloodworm and suchlike. This will provide your fish with the best colouration and health and will also encourage your fish to come into breeding conditions.

How to sex the Yellowtail Rasbora

It is relatively easy to differentiate between female and male Yellowtail Rasboras. Mature females are noticeably rounder-bellied and often a little larger than males. In contrast, males are smaller, and the yellow stripe on males is more intense than the females.