41 Types of Fish (Most Popular Saltwater and Freshwater Fish) Fish are one of the first vertebrates that came to life on this planet. They hold the basic blueprint for all different types of body structures found on the planet and has evolved into all sorts of unusual species. Registered dietitians reveal the 21 best types of fish to eat, including top picks for heart health, diabetics and more. Here's what to know. A fish is any of approximately 34,000 species of vertebrate animals found in the world’s fresh and salt waters. The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. This guide explores 120 types of fish, offering a clear look at their distinctive features, behaviors, habitats, and ecological roles. Whether you’re a beginner fish enthusiast or an experienced naturalist, these descriptions help you identify and appreciate the variety in the underwater world. Instead, there are 3 main classes, groups, or types of fish: bony fish (Osteichthyes), jawless fish (Agnatha), and cartilaginous fish (Chondrichthyes). Fish are the most diverse group among vertebrates, with over 33,000 different types of fish species. Fish are water animals that live in freshwater or saltwater and breathe through gills. Some fish are small and colorful, while others are large and used for food, fishing, or aquarium keeping. Salmon, tuna, goldfish, trout, shark, and catfish are some common examples of different types of fish. Fish are amazing water animals found in oceans, rivers, lakes, and ponds around the world. Learning different types of fish names in English with their pictures helps readers easily recognize and understand the variety of fish that live in different water environments. Fish and Game stocks over 30-million fish from its hatcheries into rivers, lowland lakes, reservoirs and mountain lakes every year. Fish have been an important natural resource for humans since prehistoric times, especially as food. Commercial and subsistence fishers harvest fish in wild fisheries or farm them in ponds or breeding cages in the ocean. From hand-battered fish and chips to grilled salmon sandwiches and creamy seafood pasta, Fresh Off the Hook brings bold, coastal-inspired flavor to the heart of the Treasure Valley.