Algae are a water-coloring agent that supplies oxygen and balances the ecosystems of pond water. Excessive occurrence of algae causes water environment fluctuations, affecting animal health. Farmers need to grasp the characteristics and developmental conditions of each algae in order to adjust, stimulate beneficial algae and limit harmful algae.
1. Common types of algae
– Algae is the main source of oxygen for shrimp’s respiration, while absorbing nutrient salts, reducing the level in water, balancing the ecology of ponds … When the density of algae will cause bloom in water, causing deficiency. Oxygen for shrimp pond at night. Good management of algae in ponds is essential.
– In the pond water environment there is always the appearance of algae: green algae, silica (algae is beneficial because it does not contain toxins, when growing in ponds cause less blooms), algae, algae Armor and eye strains (harmful as they grow in water will cause bloating, watery viscous, foam is difficult to tan, produce more toxic). Depending on the area, farming area, the ecosystem in which pond algae changes more or less. As the algae grow, the pond water will be dark blue, watery blue, floating blue on the water and smelly. Sunlight shining blue usually floats on the water, washed to the wind. When the old algae is granular or filamentous, discharging mucus into the water can cause congestion.
– In some cases white shrimp are found in the intestinal tract of shrimp in the digestive tract. For algae, when dominant in the pond will be green cheeks, or dark brown; Blue, yellow, red, brownish scum concentrates on water and bottom pond when sunlight is reduced. Algae appear and develop many manifestations of water in contaminated ponds. Shrimp do not digest algae due to their hard cell wall, in some cases the shrimp are obstructed by intestinal obstruction or faeces because of too much algae in the intestine.
2. Causes and remedies
– In intensive shrimp culture, the main cause of deteriorating water quality is due to excess food and excessive shrimp waste. The sign of redundant food is that the water becomes suddenly bluish, the NH4 +, NH3 content is abnormally increased, the shrimp is weaker … This time it is necessary to adjust the amount of food, feeding from lack to enough or can be cut. Eat food during the day to minimize the amount of organic waste caused by food.
As the end of the crop, the lower the N / P ratio in the water is due to N bottoming, so from the first culture day of the pond should be supplemented with microorganisms containing Nitrobacter and Nitrosomonas bacteria to metabolize the substances causing As toxic as NH3, NO2- into non-toxic form such as NO3-, NH4 +.
– Some notes: Nitrosomonas and Nitrobacter are light-sensitive bacteria, the appropriate pH range for Nitrosomonas is 7.8 – 8, Nitrobacter is 7.3 – 7.5. Nitrobacter will grow more slowly at the high pH characteristic of end-stage ponds. Nitrosomonas is likely to live in areas with relatively high levels of NH3 (as in pond bottom sediments).
– At 2 months of age, algae and algae are often overgrown and predominate …, the phenomenon of water hard powder floating, shrimps should stress using Yucca products. Schidigera, which combines Zeolite to alleviate the toxic gases produced by algae. On the other hand, the water before being supplied to the pond should be treated with bactericides such as Chlorine, BKC, Formaline … to reduce the algal density of water after the level.
– Drop tilapia with shrimp in the pond. Tilapia usually live in the middle and bottom layers. Fish can digest algae including algae and large plants thanks to the many fine teeth in the pharynx; The stomach acid environment of high tilapia (pH less than 2) makes the cells of algae and bacteria more fragile. Tilapia can digest 30-60% of the protein in algae, especially blue algae, green algae, reduce the biomass of this algae, reduce the water color pond to green or dark blue. , Dense … help stabilize the water color. Especially, in fish ponds, there is little light water.