The dorsal, caudal, and pectoral fins have longitudinal brown stripes on a light background; the anal and abdominal suckers are dark.

Until age two, grass gobies feed only on crustaceans, after which they start to eat fish.

In Tuzly Lagoons, they first feed on gammarids Gammarus lacustris (94%), and Idotea balthica (6%)[4] followed by fish like the big-scale sand smelt (30%) and gobies (36%).

[citation needed] On the Crimean coasts, the grass goby hosts about 27 parasite species.

In the Budaki Lagoon, the grass goby is a host of larvae of epizootic nematode Streptocara crassicauda.