Aquaculture also contributes to some degree of water pollution. All types of aquaculture waste are often dumped into nearby oceans. Fecal matter and other objectionable components then enter the open sea, leading to overall deterioration of water quality. Another problem with farming is that some of the farmed fish feed is made from wild-caught fish. In other words, a certain amount of wild-caught fish must be used to produce a certain amount of farmed fish. It is not uncommon for several units of wild-caught fish to be used to produce one unit of fish feed. Therefore, it can be argued that fish farming does not actually conserve fish stocks, but rather leads to their depletion. For example, wild fish have plenty of space in our oceans. Aquaculture, on the other hand, raises large numbers of fish in a small space. Lack of natural living conditions is therefore another problem associated with fish farming. As we have seen, it is often necessary to use several units of wild-caught fish to produce one unit of fish feed for farming. But our common sense should tell us that this cannot be considered efficient at all. With a growing world population, it is important to use resources as efficiently as possible and we cannot afford to waste them. Therefore, in order to improve the overall efficiency of fish farming, the use of fish feed made from wild-caught fish should be avoided. Another drawback to aquaculture is that certain pests that can occur in fish farms can spread to wild aquatic animals. Farmed fish sometimes escape to the sea. Secondly, if these fish carry a particular disease, even a few infected fish in the farm can infect many wild fish. Aquaculture regulations also vary widely from country to country. Some countries have fairly strict rules, while others have much looser rules. Therefore, global regulations are needed to ensure high quality standards for farmed fish in order to limit the risks and environmental issues associated with aquaculture. As we have already seen, fish farming has many advantages and disadvantages. Fish farming is the process of breeding, raising and transporting fish for domestic and commercial purposes. Because fish is a rich source of protein and other minerals, it is high on the list as a healthy and nutritious food option. It is also called combined or mixed farming. Polyculture allows different compatible species of fish to be kept in a common pond. However, different species must have different eating habits to survive different diets from a common resource. It is a useful method of fish farming. This system requires a small pond or aquarium to grow the fish. The demand for fishing is increasing day by day. Therefore, people can start fish farming by allocating space in existing fish farms. It greatly increases their income. Fish farming has fewer risk factors because the fish are kept in cages. This prevents outsiders from entering the area and catching the fish. Fish farming is the most common form of aquaculture. It involves selectively breeding fish in either freshwater or saltwater with the aim of producing a food source for consumption.