Rhinogobius Gigas

Datasheet

Behaviour

This species, Rhinogobius Gigas, is known to be robust and can exhibit aggression, particularly towards conspecifics, although it can be kept in a community tank if tankmates are chosen carefully. They are peaceful, pelagic species that do well with tankmates like Tanichthys or Danio species. It has been observed that Rhinogobius spp. can coexist with barbs, small characins, and poeciliid livebearers. However, freshwater shrimp from genera like Caridina and Neocaridina are less suitable as they may be preyed upon. In larger tanks, balitorid and nemacheilid loaches may be suitable tankmates, but in smaller setups, R. gigas should ideally be the only benthic species. It is advised not to mix this species with congeners, especially closely-related ones, due to uncertainties regarding hybridization potential. Larger fishes are best omitted from the tank, but in large setups, a few non-predatory, surface-dwelling species might be compatible. While males can be territorial with each other to an extent, serious damage is unlikely if the tank contains sufficient cover, and conspecifics are recommended for their well-being.

Feeding and Diet

Rhinogobius Gigas are opportunistic carnivores that feed on a variety of small invertebrates and crustaceans in their natural habitat. In the aquarium, they should be offered small live or frozen foods such as chironomid (bloodworm) or mosquito larvae, Artemia, Daphnia, and Mysis. While dried foods may be accepted after an acclimatization period, they should not be the primary diet for these fish.

Reproduction & Dimorphism

Reproduction in this species typically involves the male guarding eggs deposited on the ceiling of a cave or crevice until hatching. It is recommended to provide several potential spawning sites in the aquarium, such as rocks, terracotta pipes, or plant pots. Successful spawning is indicated by the pair disappearing from sight for a period, with the female being ejected once spawning is complete. Males may need multiple attempts to properly fertilize the eggs. Incubation typically lasts 9-12 days, and the fry undergo a pelagic stage before settling on the substrate. Adult males exhibit extended dorsal and anal fins, a more intense color pattern, and can grow larger than females. Gravid females will display visible eggs in their abdomen.

Habitat and Distribution

Native to eastern Taiwan, Rhinogobius Gigas inhabits middle and lower sections of river systems in Yilan, Hualien, and Taitung counties. They are found in smaller rivers, tributaries, and streams with substrates of gravel, rocks, boulders, and exposed bedrock, which experience seasonal variations in water flow rate, depth, and turbidity. The species can survive in a tropical monsoon climate characterized by high temperatures and humidity with intense rainfall, tropical cyclones, and a dry season.