The cause of weed disease is Zoothamnium sp. or other types of Protozoa clinging to the shell and gills of shrimp, causing pain and stress, if severe, the shrimp will not be able to peel. If shrimp farmers do not treat it, then shrimp will slowly give up eating and become weak, causing other diseases.
Identification of weed disease and how to check. Check the shrimp in the dining floor (hooks), see that the shrimp shell is slippery like there is slime on the shrimp shell and sometimes there is algae / algae on the shrimp shell, the shrimp shell is not clean. Laboratory examination with a Microscope will reveal Zoothamnium sp. clinging to shrimp shells and legs. After being infected, shrimp slowly weakened, reduced their appetite, and buried themselves in the mud in the middle of the pond. If not treated shrimp will die from infection from bacteria.
How to cure disease. Reduce the amount of organic matter in the pond by changing the water (if there is a settling pond). Reduce feed by 5 – 10 % for a while (to reduce excess organic matter). Use beneficial microorganisms to degrade organic matter (Example: Bacillus subtilis 1070 or BS-I). Use Formalan (drug to kill Zoothamnium to kill Zoothamnium at night.
Note: During the time when shrimp are sick, vitamin C should be mixed into the feed to help reduce stress
Algae is a disease mainly caused by the environment in which the main agents are algae, fungi, protozoa and bacteria acting on each other to form the disease.
According to Dr. Lightner, algae disease comes from free-living Protozoe in ponds or aquariums, which live suspended or live on the bottom of the pond.
Shrimp rot disease is present all over the world.
During the study in three different regions, we found that all the ponds had algae disease. However, depending on the conditions of each pond, the disease appears sooner or later.
Weeding disease occurs from the larval to adult stage, especially in the last months of the growing season.
– Mostly caused by some bacteria such as: Vibrio sp., Aeromonas sp. , … Due to some cyanobacteria: Spirulina subsalsa, Schizthrix calcicola ; Green algae: Enteromorpha sp .; Algae: Amphora sp., Nitszchia sp ., fungi and protozoa.
According to Lightner, this disease appears due to parasites, algae, bacteria … attack from the outside in.
The disease is easy to recognize, the whole body is dirty, concentrated in the cephalothorax or the whole body, gills and appendages. Shrimp affected by this disease are very weak, do not eat, move less and the edges of the shore, and gills are often damaged or change color.
Examination of parasites by microscopic examination showed that Vorticella sp. and Epistylis sp. and lots of mushrooms. PCR test on frozen shrimp has up to 80% of shrimp infected with white spot pathogen with severe intensity.
– Prevent diseases by managing pond water quality well, stabilizing algae in ponds and always ensuring oxygen demand for shrimp.
– Increase water exchange to improve the environment and stimulate shrimp molting. If the infection rate is high, we can use formol at a dosage of 15-20ppm during the day and then change the water, if the seaweed is still there, we can beat it a second time.