''Rhinogobius candidianus'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

goby The Gobioidei are a suborder of percomorph fish. Many of these fishes are called gobies. It is by far the largest and most diverse order within the order Gobiiformes, and one of the most diverse groups of ray-finned fish in general. The subord ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Etymology

The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''candidianus'' refers to the type locality, Lake Candidius. However, the species does not occur in the lake itself, but rather in the nearby rivers.

Description

''Rhinogobius candidianus'' can grow to

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

. The body is elongated, compressed posteriorly. The dead is depressed with an obtuse snout tip. The

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s are united to a rounded sucking disc. Body coloration is yellow or dark brownish. There can be 6–7 indistinct blotches on side; some adults have blue spots.

Distribution and population structure

''Rhinogobius candidianus'' is widely distributed in Taiwan. However, genetic data indicate that populations in the east and south of the island are likely resulting from introductions. Furthermore, genetic data show high population differentiation among the native populations, suggesting that this species has limited ability to disperse from one water course to another through the sea. Some sources suggest that this species also occurs in China, but there is no evidence supporting this.

Habitat and ecology

''Rhinogobius candidianus'' occurs only in

lotic River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.Angelier ...

habitats. In the headwaters of

Tamsui River The Tamsui River (alternatively Danshui River, ) is the third longest river in Taiwan after Zhuoshui River and Gaoping River, with a total length of , flowing through Hsinchu County, Taoyuan, Taipei and New Taipei City. It is located in the ...

, it is associated with microhabitats with large boulders and cobbles. It is omnivorous and feeds primarily on filamentous algae, insects, and detritus; another study characterizes its diet as mainly consisting of aquatic insects and macroinvertebrates (including freshwater crabs).

References

{{Taxonbar , from=Q3760585 , CoL-Taiwan=yes candidianus Cyprinid fish of Asia Freshwater fish of Taiwan Endemic fauna of Taiwan Taxa named by Charles Tate Regan Fish described in 1908