The tidewater goby (Eucyclogobius newberryi and Eucyclobius kristinae) lives endemically along the coast of California. A typical tidewater goby has an elongated body with a length rarely exceeding 50 millimeters. Adult fish are translucent or mostly transparent, olive-brown with darker mottling. The species shows narrow environmental preferences, mainly living in coastal lagoons, creeks, and marshes. Gobies feed on benthic invertebrates and burrow in the sand for spawning. The tidewater goby usually acts as the secondary consumer whose behavior may alter the population and structure of other organisms, especially their preys and predators. The species was listed as endangered in 1994 after a considerable decline in the population and the number of localities. Habitat loss or degradation, and pressure from introduced species threaten the survival of the tidewater goby. However, influences from other factors have also become more important recently. For example, water inflows to goby habitat may contain pesticides, which will settle and accumulate to toxic levels in benthic sediment.