Tropical fish species include saltwater and freshwater fish. However, when most hobbyists refer to a wide array of types of tropical fish species, they generally speak of freshwater fish.
You can find these fish in your local pet store, or you can check out specialty shops that cater to fish tank owners. They are captivity born and bred, and only rarely will a wildly caught fish be introduced into a fish tank for ornamental purposes.
The various types of tropical fish species which fall within the tetra family are frequent residents of residential fish tanks. They feature gorgeous colorings, are hardy enough to survive the occasional missed water change, and can also weather some temperature fluctuations.
Make sure the different types of tropical fish species get along before you put them together. Failure to ensure compatibility leads to fights, fish loss, fin nipping, and injured fish that may fall victim to various diseases, which then infect the rest of your ornamental fish population.
Discuss with a store clerk the living conditions the tropical fish you are introducing into your home tank require, what the temperature maximum and minimum ranges are, and also what lighting conditions are required.
Also, discuss food intake, and any nutritional deficiencies you observe with the tropical fish you buy. Supplementing water and food is necessary to ensure fish health, longetivity, and the health of the tank.