1) Temperature / temperature
In addition to the high temperatures of the tropics, a problem that is often found is a problem that is too extreme temperature changes due to the influence of the season, for example the rainy season. Low temperatures will cause the speed of metabolism down so that the appetite of fish and shrimp to be decreased. The cool temperature below the optimum temperature will affect the immune suppression in fish and shrimp. The optimum temperature will be different for each species of ornamental fish.
pH of the water needed by fish will vary depending on the type of fish. In general, fish and shrimp will be tolerant of a certain pH range, eg for ornamental fish types of Koi and chef pH range between 6.2 to 9.2. extreme water pH below or above the optimum pH will cause disturbances in the health of fish and shrimp. The optimum pH will vary depending on the type of fish and shrimp.
The immediate effect of low pH and the pH is too high in general is a form of epithelial cell damage, skin or gills, it will disrupt the process of absorption of oxygen, especially for fish and shrimp that breathe using gills.
Hardness on the environment ornamental fish farmers known as soft water and hard water. The value of hardness in the water is usually determined by the content of calcium carbonate or magnesium. Depth values for water hardness can be divided into soft water (low hardness), liquid water, and water is hard or high hardness and very loud.
Each species of fish and shrimp, especially ornamental fish require water hardness is not the same. Eg neon tetra fish require water hardness is low when compared to fish from the group siklid. So that when the fish are in conditions not suitable hardness can cause interference with the physiological fish causing the fish susceptible to disease.
4) Material contamination
Material contamination usually comes from water sources used in a fish and shrimp farming, especially the use of water resources of the river or other public waters.
Contamination can come from domestic waste and industrial waste. Material contamination can form toxic materials and heavy metals. The contaminant material can directly turn off or can also weaken the fish and shrimp.
At low concentrations of contamination that took place in the long term will cause effects that do not destroy fish and shrimp but disrupt fish life processes (sublethal) it will damage the health of fish and shrimp. In such conditions the fish and shrimp will be easily infected by all kinds of diseases, for example diseases caused by fungal and bacterial infections.