Rhinogobius Formosanus

Datasheet

General Description

Rhinogobius Formosanus, a member of the Gobiidae family, was previously considered a subspecies of R. nagoyae but has been recognized as distinct since 2008. It is characterized by irregular, reddish-brown lines on the cheek and opercle, distinguishing it from other Taiwanese Rhinogobius species. This species is a part of the R. brunneus group, which shares specific anatomical features such as the cheek with sensory papillae. Rhinogobius spp. have a wide distribution across continental Asia and various islands in the Western Pacific, with over 60 recognized species.

Aquarium Setup

Maintaining Rhinogobius Formosanus is not challenging under suitable conditions. It thrives in a tank designed to mimic a flowing stream, complete with a substrate of rocks, sand, gravel, and boulders. Decorate the tank with driftwood branches, terracotta pipes, and plants like Microsorum or Anubias spp. Ensure the water quality is pristine, with weekly water changes of 30-50% volume and adequate dissolved oxygen, possibly achieved through power filters or airstones.

Behavior

These gobies are robust and can display aggression, but they can coexist in a community tank with appropriate tankmates. They are peaceful, pelagic species that do well with fish like Tanichthys or Danio species. Rhinogobius spp. are suitable for larger tanks when paired with loaches but should ideally be the only benthic species in smaller setups. They may exhibit some territorial behavior with conspecifics, requiring the presence of both males and females to maintain activity levels.

Feeding and Diet

Rhinogobius spp. are opportunistic carnivores, primarily feeding on small invertebrates and crustaceans. In an aquarium, they should be offered live or frozen foods like bloodworms, mosquito larvae, Artemia, and Daphnia. While they may acclimate to dried foods, these should not be the primary diet. In the wild, they are active feeders during the summer and early autumn.

Reproduction & Dimorphism

Wild populations of Rhinogobius Formosanus have evolved a complex breeding strategy, with some populations exhibiting amphidromous behavior. In an aquarium setting, these gobies reproduce by depositing eggs beneath rocks guarded by males. The larvae drift in the water column post-hatching, requiring small food like rotifers until they can accept larger prey. Adult males are larger, display more intense colors, and have extended dorsal and anal fins compared to females.

Habitat and Distribution

Endemic to river systems in northern and northeastern Taiwan, Rhinogobius Formosanus thrives in freshwater or brackish streams. Their natural habitat in Taiwan's river systems highlights the species' preference for flowing waters. The distribution of this goby spans Russia, Korea, China, Vietnam, Laos, Cambodia, Taiwan, and several Western Pacific islands.