Rivulids

Rivulids are a family of small freshwater fish belonging to the order Cyprinodontiformes. They are commonly known as killifish or rivulus fish. These fish are found in freshwater and brackish habitats across South America, Central America, and Africa. Many species are characterized by their small size, often less than 5 centimeters in length, and vibrant coloration, particularly in males.

A notable characteristic of many rivulids is their ability to survive periods of drought. Some species can bury themselves in mud and enter a state of suspended animation called aestivation, surviving until water returns. This adaptation allows them to inhabit ephemeral pools and temporary water bodies that would be unsuitable for many other fish. Their diet typically consists of small invertebrates, insects, and insect larvae.

Rivulids are popular among aquarium hobbyists due to their striking appearances and interesting behaviors. However, their specific care requirements can vary significantly between species, and some have specialized needs regarding water parameters and diet. Conservation status is a concern for some rivulid species, as habitat destruction and degradation pose threats to their populations in the wild.