The phrase "one of the finny tribe" is typically used to describe a fish. However, there are many synonyms that can be used instead of this particular phrase. Some of these synonyms include fish, aquatic animal, sea creature, marine animal, and underwater lifeform. Other synonyms that can be used to describe species of fish include trout, salmon, bass, tuna, and cod. Additionally, specific species of marine animals such as whales, dolphins, sharks, and crustaceans can be used to describe creatures that live in the sea or in freshwater environments. Regardless of the synonym used, it is important to be descriptive and clear when discussing different creatures that live in water.