Fish and shrimp can live a normal life if the environment has water quality that is suitable for life. Water quality parameters that do not fit can be fatal to aquatic life in general. Water quality parameters were very influential in the life of fish and shrimp, among others are:
a. Temperature
Temperature greatly affects the metabolic processes of fish. Optimal water temperature (as required in the tropical fish) is 27-31 o C. On the water temperature below 250C can reduce the rate of metabolism of the fish, so the fish will be stunted. Meanwhile, when the water temperature is above 350C can lead to fish kills.
DO or solubility of oxygen in water is a critical factor for fish farming. Oxygen is a basic requirement for water biota in general. The air in the atmosphere containing oxygen as much as 20.95% of the volume of air. While in the water solubility of oxygen measured in mg / liter of water or oxygen by weight (mg) per million mg of water (ppm). The solubility of oxygen depends on;
1. Water temperature
2. Air Pressure
3. The vapor pressure of water
Table 1. The solubility of oxygen saturation in pure water at various temperatures (T – ° C) in air pressure 760 mm Hg (1 atmosphere)
The process of oxygen into the blood of fish
More oxygen into hemoglobin is regulated by the oxygen pressure. In the gills pressure of oxygen in water is higher than in the blood, so that oxygen can enter the blood hemoglobin. In the Oxygen network used very quickly, causing the oxygen tension in the tissues was lower than in the blood, hemoglobin releases oxygen from the blood into the tissues.
Table 2. Effect of oxygen on fish
According to Brown (1987) 1 ° C increase in temperature will increase the oxygen consumption of about 10%. To sustain life, the living creatures that live in the water both plants and animals depend on the levels of dissolved oxygen. Oxygen fluctuates daily (diurnal) and seasonal depending on the mixing (miksin) and prgerakan (turbulence) of water mass, respiration and photosynthesis activity of sewage (effluent) that goes into the water body.
In freshwater, dissolved oxygen levels between 15 mg / l at a temperature of 0 ° C and 8 mg / l at a temperature of 25ºC. Oxygen is necessary for the ecosystem cultivated. The presence of oxygen is very influential on the level of resistance Ecosystem (fish) itself in order to sustain life. Levels of dissolved oxygen in a container of fish farming should range between 7-9 ppm. The dissolved oxygen concentration was decisive in aquaculture. Osigen levels dissolved in the container of fish farming can be determined in two ways, namely by titration and by using a device called a meter DO (dissolved oxygen).
c. pH
The pH is a measure of the standard ratio of H + ions and ion OH-, when under normal circumstances the number of both types of ion referred neutral indicated by pH = 7. The circumstances in which the more water ions H +, then the water is declared acidic (pH <7) and conversely the circumstances in which the water more OH- ions, then the water is declared alkaline (alkaline – pH> 7). Standard pH required in most aquatic biota is 6.8 to 8.5.
If the water becomes acidic, pH below 4 then the fish will spend a lot of mucus that interfere with breathing, as well as when the pH is above 8. It is necessary for water quality measurements at regular intervals to maintain the quality of water in normal conditions.
d. alkalinity
e. hardness
f. ammonia
g. Nitrite (NO2) and nitrate (NO3)
h. Hydrogen Sulfide (H2S)
i. plankton
j. Salinity