The blackline rasbora, Rasbora borapetensis, is a fish of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Cyprinidae found in Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 in the Mekong

Mekong

The Mekong is a river that runs through China, Burma, Laos, Thailand, Cambodia and Vietnam. It is the world's 10th-longest river and the 7th-longest in Asia. Its estimated length is , and it drains an area of , discharging of water annually....

, Chao Phraya, and Mae Klong

Mae Klong

The Mae Klong is a river in western Thailand. The river begins at the confluence of the Khwae Noi or Khwae Sai Yok and the Khwae Yai River or Khwae Si Sawat in Kanchanaburi, pass Ratchaburi Province and empties into the Gulf of Thailand in Samut Songkhram....

 basins, and also the northern Malay Peninsula

Malay Peninsula

The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...

. In the aquarium trade, it is known by a variety of other names, including red-tailed rasbora, bora bora rasbora, and brilliant rasbora.

Description

The blackline rasbora is a streamlined, silver fish with a dark brown or black, mid-lateral stripe reaching from the gill

Gill

A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

 opening to the front of the caudal fin base. Above this line is a gold stripe. The caudal fin is bright red, and unlike Rasbora einthovenii, there is no black pigment. The two sexes look alike, but adult females are slightly larger than males. The fish grows to about 2.5 inches or 6 cm in length.

Habitat

The blackline rasbora swims from the midwater level to the surface in ponds, ditches, canals, and reservoir margins of 2 m depth or less. It prefers a pH

PH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 range of 6.5 to 7.0, water hardness (dH) of 5 to 12, and temperatures between 22 and 26 °C.

In the aquarium

The blackline rasbora is a popular aquarium

Freshwater aquarium

A freshwater aquarium is a receptacle that holds one or more freshwater aquatic organisms for decorative, pet-keeping, or research purposes. Modern aquariums are most often made from transparent glass or acrylic glass. Typical inhabitants include fish, plants, amphibians, and invertebrates, such as...

 fish that prefers slow moving water and a heavily planted tank. It is a true schools

Shoaling and schooling

In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...

fish and will almost always be observed in a tight school, racing back and forth in the middle and upper aquarium levels. It is a hardy, peaceful fish which can be housed with other peaceful species such as loaches, small and large tetras, livebearers, plecos, and rainbowfish.