Rhinogobius candidianus (Regan, 1908)

Size

Rhinogobius candidianus can reach a standard length of 7.8 cm (3.1 in).

Body and Head Shape

It has an elongated body that becomes compressed toward the posterior end; its head is depressed, with an obtuse tip to its snout.

Pelvic Fin Structure

Its pelvic fins are fused to form a rounded sucking disc.

Coloration

Body coloration ranges from yellow to dark brownish, with 6–7 indistinct blotches along the side, and some adult individuals also have blue spots.

Distribution in Taiwan

This goby is widely distributed across Taiwan; however, genetic analysis indicates that populations in the island’s eastern and southern regions are likely the result of human introductions.

Population Differentiation

Genetic data also shows high levels of population differentiation between native populations, which suggests the species has a limited ability to disperse between separate watercourses via the sea.

Distribution in China

While some sources list this species as also occurring in China, there is currently no evidence to confirm this occurrence.

Habitat Type

Rhinogobius candidianus lives exclusively in lotic, or flowing freshwater, habitats.

Microhabitat Preferences

In the headwaters of Taiwan’s Tamsui River, it is most commonly found in microhabitats that feature large boulders and cobbles.

Trophic Classification

It is an omnivorous species.

Diet Composition

One record notes it feeds primarily on filamentous algae, insects, and detritus; a separate study records its diet as consisting mainly of aquatic insects and macroinvertebrates, including freshwater crabs.