Tubenose goby

Identification

The tubenose goby is the smallest of the three Ponto-Caspian gobies in the Netherlands, reaching 8 to 12 cm. The body is slender and light brown with a characteristic marbled pattern of dark spots — hence the Dutch name "marmergrondel." The most distinctive feature is the tubular nostrils that protrude above the upper lip like small tentacles. The head is relatively small and rounded. Like all gobies, it has fused pelvic fins forming a sucker disc. The difference from the other gobies: the tubenose is smaller, slimmer, and has the conspicuous tube-shaped nostrils.

Behavior & ecology

The tubenose goby is a bottom fish that lives among stones, riprap, and bank vegetation in both flowing and still water. It feeds on small invertebrates: worms, midge larvae, amphipods, and snails. The species is less tied to hard substrate than the round goby and is also found in softer habitat — transition zones between river and polder. During spawning, the female attaches eggs under stones, which the male guards. The tubenose goby originally comes from the lower reaches of rivers around the Black Sea.

In the Netherlands

The tubenose goby is the third Ponto-Caspian goby species in the Netherlands, alongside the round goby and the monkey goby. It was first recorded around 2002 and occurs in the major rivers and their branches. Of the three invasive gobies, the tubenose is the least abundant and least aggressive. Its impact on native bottom fish is likely smaller than that of the round goby, but the species does occupy the same hiding spots as the protected bullhead.