Rhinogobius Flumineus

Datasheet

General Description

Rhinogobius flumineus, commonly known as the Japanese Rhinogobius, belongs to the Gobiidae family within the Perciformes order. It is a small fish species, with a maximum size of around 6.0cm. The species displays distinct characteristics that differentiate it from other similar members of the genus, including specific fin morphology and color patterns.

Aquarium Setup

To successfully maintain R. flumineus, an aquarium setup resembling a flowing stream is recommended. This involves a substrate of various-sized rocks, sand, fine gravel, and water-worn boulders. Additionally, the tank can be decorated with driftwood branches, terracotta pipes, plant pots, etc., creating hiding spots and broken lines of sight. While most aquatic plants may struggle in such an environment, hardy varieties like Microsorum, Bolbitis, or Anubias spp. can be grown attached to the decor. Clean water conditions are crucial for the well-being of these fish, necessitating routine 30-50% water changes and ensuring high oxygen levels with the help of power filters, additional powerheads, or airstones if needed.

Behaviour

Behavioural patterns of R. flumineus indicate a preference for habitats in freshwater environments, particularly smaller rivers, tributaries, and streams with gravel, rocks, boulders, and exposed bedrock substrates. The species' life cycle remains entirely freshwater despite coexisting with amphidromous relatives in certain locations.

Feeding and Diet

As opportunistic carnivores, R. flumineus feeds on various small invertebrates and crustaceans in its natural habitat. In an aquarium setting, they should be provided with live or frozen foods such as chironomid larvae, Artemia, Daphnia, and Mysis. While dried foods may be accepted after acclimation, they should not be the primary diet source.

Reproduction & Dimorphism

Mentioned only as a behavioural trait rather than specific information on the species.

Habitat and Distribution

The Japanese Rhinogobius is endemic to Japan, primarily found in central and western regions of Honshu, along with the islands of Kyushu and Shikoku. This species thrives in freshwater bodies like rivers and streams with variable water flow rates and depths. Its distribution encompasses specific prefectures in Japan, with the type locality being the Sôshagawa River at Oshita, Ochigun District, Ehime Prefecture, Shikoku.

Unique to the Rhinogobius genus, R. flumineus is part of a group of closely related species that are predominantly found in continental Asia, spanning Russia, Korea, China, Vietnam, Laos, Cambodia, as well as various Western Pacific islands like Japan, Taiwan, and the Philippines. The genus includes over 60 recognized species, categorized into nominal taxa pending further study and description.