Sand goby spot at the rear of the first dorsal fin, ringed with white. The fish has a slender body, and the head is about a quarter of the total length. The sand goby has two dorsal fins with a wider gap between them than the common goby ("Pomatoschistus microps"), the anterior one consisting of six soft spines and the posterior one eight to eleven soft rays. The pelvic fins are fused with the anal fins. There are 58 to 72 scales along the lateral line and these scales are rather smaller than those of the common goby. The caudal fin is
Monkey goby as amphipods and shrimp. In the Danube lakes Yalpug and Kugurluy, the diet of the monkey goby consists of amphipods, molluscs, and Oligochaeta. In the Khadzhibey Estuary a dozen species of prey make up the diet of monkey goby. Polychaetes, larvae of insects, and shrimp are present in the diet year round. Seasonal dietary additions include crabs such as "Rhithropanopeus harrisii", sea weed such as "Zostera marina", and amphipods such as "Marinogammarus olivii". Certain planktonic crustaceans are also present in the diet of adult gobies. In the northwestern Black Sea, twelve parasite species are known to infect the monkey goby.