freshwater community4


Rio Pearlfish

rio pearlfish

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Scientific Name:   Nematolebias whitei      
Min. Tank Size:   15 gallons      
Personality:   Peaceful/Males can be aggressive      
Temperature:   68-73°F      
pH:   6.0-7.0/0-8°dGH      
Size:   3"      
Diet:   Carnivore/May accept flakes      
Breeding:   Egglayer      


Best kept in a species tank.

Rio Pearlfish

This species is native to South America and can be found throughout the Laguna de Araruama basin and Das Ostras River basin as well the coastal plains and mouth region of the Sao Joao River in Brazil. These fish are an annual species and thus tend to inhabit bodies of temporary water such as pools and streams in floodplains as well as lagoons. Rio Pearlfish are typically dark brown in color and exhibit a number of tiny light blue dots all over their bodies and fins. In some specimens these dots coalesce to form lines along the body. The dorsal and anal fins of this species are often pointed and may exhibit bands of reddish brown and yellow in addition to several light blue spots.

Tank Set-up

In the home aquarium, Rio Pearlfish are not picky in regard to water quality and can adapt to a variety of tank conditions. However, regular partial water changes are still a necessary part of maintaining this species. These fish prefer planted tanks that provide cover and may also enjoy floating plants to diffuse the lighting in the tank. Lighting isn't absolutely necessary but will enhance the beauty of the Rio Pearlfish.  


This species is likely to accept any foods offered including a variety of flake, frozen and live foods. To simulate their natural diet, Rio Pearlfish should be fed a combination of meat-based foods and algae flakes or wafers. Bloodworms, Daphnia and a Spirulina-based flake or pellet would be a good choice.


In the wild, these fish die every year during the dry season and leave behind their eggs. When the rainy season returns, the eggs hatch and grow very quickly, reaching sexual maturity in as short a time frame as six weeks. Breeding this species in the home aquarium is a little tricky but it can be done. The spawning tank should be lined with boiled peat and, one the fish have spawned, the peat containing the eggs should be slightly dried and kept in a plastic bag. After about 12 weeks, wet the peat in a shallow tub and wait for the fry to hatch. Newly hatched fry can be fed baby brine shrimp or microworms.

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