Animal-World > Freshwater Fish > Cyprinids > Slender Rasbora

Slender RasboraGold Line Rasbora ~ Black Line Rasbora
Striped Rasbora ~ Striped Barb

Family: Cyprinidae

• Puzzles
• Postcards

Rasbora daniconiusPhoto © Animal-World: Courtesy Ken Childs

    The Slender Rasbora is a great fish for the aquarist looking for a less common species to add interest to their tank!

    The Slender rasbora isn't as colorful but is just as beautiful as its flashier cousins. Their most prominent feature is a blue-black line that runs the body length. This line is very finely outlined in gold. It is this feature that has inspired several rather descriptive names, including Black LIne Rasbora and Gold Line Rasbora.

     In the wild, this fish may be found swimming the rivers in schools with hundreds of individuals. So a school is a must, and the more individuals the better. These fish do fine in community tanks but will suffer in the company of aggressive fish. Slender Rasboras really look beautiful in a tank that simulates their habitat with plants, rocks, wood and substrate. Keeping the Slender Rasbora does require some mastery of water chemistry. Fluctuations in water quality leave this fish weak and prone to disease.

For more Information on keeping freshwater fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:      The Slender Rasbora was described by Hamilton in 1822. They are found in South East Asia: Mekong, Chao Phraya and Salween basins, northern Malay Peninsula, and Sri Lanka. They inhabit all sorts of waterways from ditches, streams and pond, to flooded fields. But they are primarily found in sandy streams and rivers with slow moving waters. They can be found in large schools feeding at the surface on small aquatic insects and detritus.

Status:      These fish are not endangered.

Description:      The Slender rasbora is a slim fish, as the common name implies. The general body color is silver, with olive colored undertones. The belly will be whiter. These fish have a striking blue-black line that runs the whole body length, right through the tail. This line is finely outlined with gold. Scales are large and highly reflective. Fins are small and yellow.

Size - Weight:      The Slender Rasbora has been reported to reach 5 inches (12.5 cm) in the wild but usually only reaches 3.5 inches (9 cm) in the home aquarium.

Care and feeding:      Slender Rasboras are omnivores. A good balance of prepared and live foods is required for optimal health. Daphnia, brine shrimp, and bloodworms all make excellent choices for live foods. Some green foods like lettuce are good too. Dip a washed lettuce leaf in boiling water to soften it. Take care to remove the uneaten lettuce from the tank within a few hours.
     The key to making this fish extra beautiful is making it feel at home. Setting up a habitat simulating tank is the best way to do this. A sandy or fine gravel substrate with a few smooth rocks and pebbles is a good start. If you get the right water chemistry for this fish, many aquatic plant species can flourish. Look to our Aquarium Plant section for some good ideas. Aquarists who really want the natural feel could add some aquarium sealed dried bamboo to simulate the reeds that grow along the shoreline of their natural habitat. Reasonable water current is also pleasant for these fish. Since these fish are quite active, they tend to do better in larger and longer aquariums where they can school.

Water Region: Top, Middle, Bottom:      The Slender Rasbora is a mid-water fish.

Acceptable Water Conditions:      Temp: 71 - 80 ° F (22 - 27 ° C)
     pH: 7.0 - 7.5
     Hardness: 8 - 17 ° dH

Social Behaviors:      The Slender Rasbora requires a sizeable school of at least 5 individuals to display healthy coloration and behavior. Although they occasionally quarrel, they are generally good natured. These fish are quite active. They should be mixed with fish of similar temperament.

Sexual Differences:      The females are slightly plumper and deeper bodied.

Breeding/Reproduction:      The Slender Rasbora can be bred fairly easily. A large tank is required for spawning as part of the courtship is a very intense chase. A pair will spawn on fine leaved plants, so be sure to include Hornwort, Cabomba, Milfoil, or a similar species in the breeding tank. Java moss or Crystalwort (Riccia) work too if they are anchored down. The parents will prey upon their young, so they should be removed once eggs are scattered. The fry must be fed liquid fry food or the smallest live foods until they can swallow crushed flake food.

Availability:      The Slender Rasbora is difficult to find, but specialized fish stores may carry them. They are sometimes available online but as of yet not consistently. Cost should be somewhere in the $2.00 - $6.00 USD range.

Author: "Yvonne"
Additional Information: Clarice Brough, CFFS.

Comments
Add a new comment!
Latest Comments
I got five of these rasboras, as well. They were in a tank at the LFS with a hodgepodge of fish, all priced at $2 a piece. They were washed out and I thought they were red-lined rasboras, so I got them to add to my school. Anyway, I got them home and as they colored up a little, I could see they had a gold line. The black line colored up as well. After trying two other tanks where they didn't seem happy, I finally put them in a 20-gallon with some checkered barbs and harlequin rasboras. Then they settled down and their colors came out in full glory. I think these fish are real beauties. The color combination is great, so I think I really lucked out by mistake. Reply janek51 2007-11-15
I have a shoal of 5. They are top swimmers in my 24" deep tank. They seem very easy to keep, are very active, and I would recommend them highly. Reply chris 2007-06-14
Add a new comment!

Back to Cyprinids