Care
The Red-tail Rasbora is abundant throughout the Chao Phraya, Mae Klong, and Mekong River Basins. Here it inhabits the still or slow-flowing waters of thickly-vegetated canals, ditches, drains, shallow ponds, swamps, and flooded areas such as rice paddies. This fish is a peaceful midwater shoaling species that should be maintained in groups of 6 or more. A mature, heavily planted tank would be ideal to showcase this species, as their colours intensify when settled into a well planted environment. Dark substrate and background choices, along with some spindly driftwood and shady caves will also help them to settle in. Tankmates should be of similar size and temperament and enjoy the same soft, acidic conditions. Filtration should be efficient but the flow very gentle as these fish are used to sluggish waters. The Red-tail Rasbora (R. borapetensis) occurs sympatrically over some of its range with the very similar-looking congener R. rubrodorsalis. They can be told apart as follows: R. rubrodorsalis has a bright red dorsal fin blotch, which is absent in R. borapetensis.
Feeding
Flake, small sinking pellets/granules, and small frozen foods such as mosquito larvae, vitamin-enriched brineshrimp, cyclops, and daphnia.
Breeding
This is an egg-scattering species that spawns on a continual basis, in much the same manner as many of the rainbowfish. In a densely planted aquarium, small numbers of fry may simply appear from time to time. However, if you wish to raise larger numbers, a separate spawning tank should be set up. Ideally, this will be shallow but long (and well covered) with a layer of marbles as a substrate and numerous clumps of fine-leaved plants. The temperature should be set at the higher end of the preferred range, and a gentle air driven sponge filter placed on the tank. A well-conditioned pair should be carefully acclimatised to the breeding aquarium, and spawning will either occur naturally when the first rays of morning sunlight hit the aquarium glass, or they can be triggered into spawning by performing a small, slightly cooler water change. Eggs will be scattered in batches amongst the plants and marbles, and most should fall to safety. Once spawning eventually appears to cease, the parent fish should be removed to avoid predation. The eggs are somewhat sensitive, but under good conditions should hatch within 24-48 hours (temperature dependent). The fry should become free-swimming a further 24-48 hours later and can be fed on infusoria, Artemia nauplii and finely crushed egg-layer first foods.
