Pygmaea Rainbow - Melanotaenia pygmaea

The "Pygmaea Rainbow" is a common name that typically refers to a specific species of rainbowfish known scientifically as Melanotaenia pygmaea. 

Size:

They are one of the smallest rainbowfish species, typically reaching only 4-5.5 cm (1.6-2.2 inches). 

Appearance:

Males are more brightly colored than females, with a metallic blue body, a reddish-brown head, and whitish fins. Females have smaller fins and lack the reddish head coloration. 

Natural Habitat:

They are found in two small tributaries of the Prince Regent River, in the Kimberley region of Western Australia. They inhabit freshwater pools and rivulets on sandstone terraces, often near waterfalls and rapids. 

Social Behavior:

They are schooling fish, typically found in groups of 50 or more. 

Aquarium Keeping:

They are relatively easy to keep in aquariums, provided they have clean, well-maintained water. They are not overly fussy about water conditions, but some hobbyists recommend a temperature of around 27°C (80°F). They appreciate a tank with plants and some open space for swimming. 

Diet:

While their natural diet is not fully known, they are thought to feed on small insects, algae, and crustaceans, similar to other small rainbowfish. In captivity, they readily accept a variety of foods including flakes, frozen foods, and live foods.