Effects of Protein Concentration in Fish Feed on Physical and Chemical Water Pollution

One of the seven characteristics of life is the ability to produce waste. Waste is the excess material an organism excretes after carrying out metabolic processes. Aquatic organisms like fish produce not only physical waste but also chemical wastes such as ammonia. Ammonia is excreted through fish gills and through their feces. In open aquatic environments, like oceans, rivers, and gulfs, this ammonia follows a nitrogenous pathway but is quickly eliminated from the system by plants, bacteria, and other microorganisms. In closed aquatic environments like aquaria and ornamental ponds, this ammonia also follows a nitrogenous pathway. As ammonia levels build-up from fish waste, a specific kind of bacteria called Nitrosomonas begins to grow. Nitrosomonas oxidizes this ammonia to produce nitrite. As nitrite levels build up, another bacteria called Nitrobacter begins to grow. Nitrobacter oxidizes this nitrite into nitrate. There is no bacteria in aquaria that can eliminate this nitrate, and thus, nitrate can only be removed by replacing the water. Ammonia and nitrite are incredibly toxic to aquatic life while nitrate is less toxic, but can get unhealthy at high concentrations. As long as ammonia is being produced, and the necessary bacteria are present, ammonia will be continually oxidized and nitrate will build up. This research project determined three things. 1. How protein concentration in fish feed affected the build-up of nitrates 2. How protein concentration in fish feed affected the physical water clarity. 3. What concentration of protein ended up in the feces. Three different fish foods with a minimum protein concentration of 42%, 36%, and 28% were fed to three different species of fish: Pterophyllum Scalare (freshwater angelfish), Cyprinus rubrofuscus (Koi), and Carassius auratus (Tamasaba Goldfish). Each kind of food was fed to each species of fish for five days. At the end of this period, nitrate readings were taken to analyze the chemical pollution of the water. To analyze the physical pollution of the water, the turbidity of the water was measured. To do this, a sample of fecal matter from each fish species from each type of food was diluted and mixed in water. After the feces settled out, the supernatant was analysed in a spectrophotometer. To sum everything up, This research experiment determined how the protein concentration of fish food affected both the chemical (nitrate and protein) and physical pollution (turbidity) of aquariaand ponds.