Texas Parks and Wildlife Code - PARKS & WILD § 31.064. Lights

A vessel or motorboat when not at dock must have and exhibit at least one bright light, lantern, or flashlight from sunset to sunrise in all weather. A vessel or motorboat when underway between sunset and sunrise in all weather must have and exhibit the lights prescribed by the commandant of the Coast Guard for boats of its class. No other lights that may be mistaken for those prescribed may be exhibited.