Hydrophilius

Hydrophilius is a genus of small, freshwater fish belonging to the family Cyprinidae, which includes minnows and carps. The genus is native to Southeast Asia, with species found in rivers and streams of countries such as Indonesia, Malaysia, and the Philippines. Hydrophilius species are typically small, with most species reaching lengths of 10-15 centimeters. They have a slender, elongated body, and their coloration varies among species, ranging from olive-green to brown or gray.

Hydrophilius fish are known for their unique reproductive behavior. During the breeding season, males construct bubble nests using air bubbles from the water surface. The females deposit their eggs into these nests, where the males guard and aerate them until the fry hatch. This behavior is a notable adaptation to the freshwater environment, as it ensures the survival of the offspring by providing a suitable habitat with adequate oxygen.

Hydrophilius species are generally considered to be peaceful and non-aggressive towards other fish. They are omnivorous, feeding on a variety of small aquatic organisms, including insects, crustaceans, and plant matter. Due to their small size and specific habitat requirements, Hydrophilius fish are not commonly kept in home aquariums. However, they are of interest to ichthyologists and aquarists specializing in Southeast Asian freshwater fish.

The genus Hydrophilius was first described by the German ichthyologist Franz Steindachner in 1866. It is currently recognized to include at least 12 species, with new species occasionally being described as more is known about the diversity of freshwater fish in Southeast Asia.