UMT MOOC: Ornamental Fish Culture - Topic 4: Nutrition of Ornamental Fish - Carbohydrates and Minerals

Carbohydrates
Besides protein and lipids, carbohydrates is the third essential nutrients which provides a cheap energy source in fish diet.  Elements within a carbohydrates contains carbon, hydrogen, and oxygen. Carbohydrates can be grouped into three classes of: (1) Monosaccharides (simple sugar), (2) Oligosaccharides (groups of Monosaccharides), and (3) Polysaccharides (stashes).

Herbivorous (plant eating) fish digest carbohydrates differently. Koi and Goldfish uses bacterial (microflora) in its gut to digest complex carbohydrates. For examples, Goldfish have carbohydrates digestibility of 70% while Moonlight Gourami, 50%.

Minerals
This is another essential nutrient in fish diet to provide needed functionalities (tissue formation, metabolism, and regulation) in living organism. As minerals cannot be produced naturally by living organism, it's obtained from external sources. When a food or body is burnt, minerals are contained within the ashes. Two classes of minerals which are: (1) Macrominerals ,which are required in large quantity (Calcium, Chloride, Magnesium) and (2) Microminerals, needed in smaller quantity (Chromium, Cobalt, and Copper). As natural soluble minerals are found within the water environment, optimal minerals requirement in fish dietary proved to be difficult. However, numerous researches have done to find the baseline requirements. For example, the table below (Source: Sales, James & Janssens, Geert. (2003). Nutrient requirements of ornamental fish – A review) shows mineral requirements for popular ornamental fish species like Tiger barb and Guppy.


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