Enters estuaries, salt marshes and pools (Ref. 4343); usually on sand or mud (Ref. 59043). Prefers brackish water. Feeds on small crustaceans, worms, chironomid larvae and mites (Ref. 4696). Its burrowing habit allows it to survive low water levels and to avoid predators (Ref. 30508). Spawns after first winter, at sea, in February - September, depending on latitude; individual females spawn several times during a season. Adhesive eggs (0.9 x 0.7 mm) are deposited under or between stones, shells and aquatic plants and males guard the eggs until hatching. Juveniles enter freshwater habitats in late summer to forage (Ref. 59043). The male defends and aerates the eggs for about 9 days.