About the Scissortail Rasbora
Species Type: Freshwater Fish
Care Level: Very Easy. Will tolerate a wide range of water parameters including pH, temperature and hardness. Can tolerate higher nitrate levels than other fish and is hardy enough to withstand the cycling process. Will readily eat prepared foods and has no special care requirements.
Origin: Mekong and Chao Phraya basins in Laos, Thailand and Cambodia, Malay Peninsula, Sumatra, and Borneo. Found in lakes, swamps and slow-flowing streams and rivers in forested areas, close to the surface.
Compatibility/Temperament: Very peaceful, suitable for a community aquarium of non-aggressive fishes, remembering its adult size (it would likely eat smaller fish). Should be kept in a group of at least six.
Being quite adaptable in its water parameters, this is a good fish for beginners provided the aquarium is larger; 48 inches minimum length to allow sufficient swimming room for this active fish. Well planted around the sides and back, with a dark substrate and floating plant cover, would be ideal. A good fish for a river aquascape including the smaller barbs, danios and loaches. Being a surface fish, the tank must be covered as the fish will jump.
Females are rounder and slightly larger than males. A typical cyprinid, it is an egg-scatterer, and adults will eat the eggs if not removed. Easy to spawn; in good condition, it will frequently spawn, and some fry may survive in a well-planted aquarium.
This species bears a resemblance to two others, Rasbora caudimaculata and R. spilocerca. The latter is a smaller fish, and the former has red colouration in the caudal fin which is lacking in the subject species. The common name "scissortail" comes from the twitching motion of the caudal fin lobes when the fish is stationary. The yellow colouration in the caudal fin varies, presumably due to different geographical locations of the wild fish.
The species was described by F. Steindachner in 1870. The species name trilineata refers to the three lines along the fish's side. In 1934, H.W. Fowler described a fish as Rasbora stigmatura; in 1972 Brittan determined this was the same species and this name now has synonym status.
Rasbora has been a "catch-all" genus for 138 species of small minnow-type fish. Ichthyologists have especially during the last two decades questioned the relationships between many of these species, and Maurice Kottelat and others recognized that the genus was polyphyletic [Greek, "of many races"] which in this instance means it contains species whose last common ancestor is not included. Several species were subsequently transferred out of Rasbora into Microrasbora [now considered a Danio], Boraras and Trignonstigma; these latter two are monophyletic, meaning that they include the ancestor and all descendants.
In 2009, Te Yu Liao, Sven Kullander and Fang Fang published the results of a phylogenetic study of the genus Rasbora; recognizing that the genus was not monophyletic, they erected four new genera for several of the existing species on the basis of osteological characteristics. This resulted in six clades within the former Rasbora genus; the subject species occurs in the sixth clade, and because the type species for the genus is also within this group, it retains the original genus name of Rasbora.
Scissortail Rasbora Diet
Naturally feeds on insects, worms and crustaceans; accepts surface foods, frozen bloodworms, daphnia and artemia, live insects.
Attains 6 inches.
Minimum Tank Suggestion
48 inches in length.
Ideal water parameters for Scissortail Rasbora
Soft (hardness < 12 dGH) acidic to basic (pH 6 to 8) water, temperature 22-25C/73-77F. Given the fish's natural adaptibility in its habitat waters, it should fare well within these ranges.