Oxygen
Fish require a certain amount of dissolved oxygen in the water. This amount of oxygen may vary from species to species, but the need never goes away.
Nutrients
Fish have a specific requirement for nutrients, which can be achieved by feeding on organic matter or other fish. These energy intakes can come in the form of lipids, carbohydrates, proteins, vitamins and minerals.
Salt
Some fish have the ability to live in either salt or fresh water, while other species have a very limited tolerance for either salt or freshwater. These requirements differ significantly with each type of fish.
Water Flow
Different fish have adapted to living in different zones of flowing water. For example trout need fast-flowing cool water, while sunfish can only survive in slow-moving waters.
Other Dissolved Compounds
Water as a liquid has the capacity to dissolve many things besides oxygen. These compounds can be naturally occurring items such as carbon dioxide, potassium, phosphates or ammonia. Various man-made compounds containing mercury, zinc, copper or tar acids, can sometimes be found in aquatic systems. All of these can affect the lives of fish in different ways.
Article Written By Henri Bauholz
Henri Bauholz is a professional writer covering a variety of topics, including hiking, camping, foreign travel and nature. He has written travel articles for several online publications and his travels have taken him all over the world, from Mexico to Latin America and across the Atlantic to Europe.
