Genus Pholis is a scientific term used to classify a group of marine fish that belong to the family Pholidae. These fish are commonly known as gunnels or butterfishes and are found in the coastal waters of the North Atlantic and the Pacific Ocean. The genus Pholis has several synonyms including Platuli, Amphipholis, and Lepidobranchus. These synonyms are used interchangeably in scientific literature for the same group of fish. The gunnels or butterfishes are characterized by their elongated bodies, serrated dorsal fins, and camouflaging coloration. These fish play an important role in the marine food chain as they are prey for larger fish species such as cod and halibut.