5.9B understand the methods used to farm large numbers of fish to provide a source of protein, including maintaining water quality, controlling intraspecific and interspecific predation, controlling disease, removing waste products, controlling the quality and frequency of feeding, and selective breeding

There are a lot of methods to fish farming:

1. Maintenance of water quality
- water is filtered to remove harmful bacteria to prevent diseases and to maintain high oxygen levels for aerobic respiration.

2. Control of interspecific predation/intraspecific predation
- interspecific competition: competition between different species. Fishes of different species can be separated by fences, nets, and tanks to prevent interspecific competition
- intraspecific competition: competition within the same species. Fish can be separated by size and age using nets.

3. Control of disease
- fish are given antibiotics to increase resistance and to decrease the chances of spreading disease, hence increasing chances of survival.

4. Removal of waste product
- water can be filtered to remove wastes such as feces and sewage
- fences, nets, and tanks can be cleaned to remove waste products.
- the location of fish can be changed from time to time to ensure the cleanness of water.

5. Quality and frequency of feeding
- fish are fed in nutritious diets in small quantities to ensure growth and prevent overconsumption/predation.

6. Use of selective breeding
- farmers may use selective breeding to allow only the fast-growing fish to reproduce, resulting in large populations of fish.