Neon Blue Rasbora (Sundadanio Axelrodi) is also known as Blue Axelrodi Rasbora, and they are a type of Rasbora fish. These fish only reach 1 inch (2.5cm) in size, so they are well-suited for nano tanks. Compared to other popular fish in the aquarium hobby, Neon Blue Rasbora are quite rare.
Neon Blue Rasbora originate from the Greater Sunda Islands of Borneo and Sumatra. They are occasionally found in the Riau Archipelago and Bangka Island off the east coast of Sumatra as well. Within these regions, they inhabit blackwater streams, pools, and swamps that consist of aged forest peat. Their native habitats are currently under threat due to rubber and palm oil plantations, building development, and various other human activities.
These fish have amazing colors of blue, green, and red. The top half of their body is a shade of bright iridescent blue. The mid-lower part of their body is usually a reddish-copper color, and the rest of their body is quite transparent and clear.
The male Neon Blue Rasbora is brighter coloration and a slimmer body compared to the female fish. The males also have a black anal fin, which tends to be darker if it is a dominant male.
Another interesting trait of the male Neon Blue Rasbora is that they are able to produce a small croaking or chirping sound when stressed. For example, they may make this sound when taken out of the water. The males croak when they are battling each other for dominance as well.