Dear friend Senthilkumaravelan Ayyar

The green coloration of the shrimp larval rearing tank water can be attributed to the presence of excessive algae growth, particularly the live microalgae Thalassiosira weissflogii in your case. Algae bloom occurs when there is an abundance of nutrients, such as nitrogen and phosphorus, in the water, providing favorable conditions for algal growth. The high nutrient levels can be a result of excess feeding or inadequate water exchange and filtration in the tank.

To address the green water issue, you can consider the following measures:

1. Adjust feeding practices: Ensure that you are providing an appropriate amount of feed to the larvae and avoiding overfeeding. Excess feed can contribute to the nutrient load in the water.

2. Optimize water quality parameters: Monitor and maintain proper water quality parameters, such as temperature, pH, salinity, and dissolved oxygen levels. Regular water exchanges and filtration can help dilute and remove excess nutrients.

3. Enhance water circulation: Improve water circulation and aeration in the tank to disrupt algal growth and promote better water quality. Consider using appropriate pumps or air stones to enhance circulation.

4. Use UV sterilization: Incorporate a UV sterilizer into the filtration system to control algae growth. UV light can help eliminate algae and reduce the green water problem.

Regarding the Vorticella infestation issue, Vorticella is a common ciliate protozoan that can attach to surfaces in the water, including the larvae. It can cause harm and lead to high mortality rates. To prevent or reduce Vorticella infestation, you can consider the following strategies:

1. Maintain clean surfaces: Ensure that tank surfaces, including tank walls and equipment, are properly cleaned and free from debris or organic matter where Vorticella can thrive.

2. Improve water quality: Implement proper water quality management practices, including regular water exchanges, filtration, and maintenance of optimal water parameters, to create an environment less conducive to Vorticella growth.

3. Use appropriate treatments: Consult with aquatic health professionals or experts to identify suitable treatments or additives that can help control Vorticella infestation without harming the shrimp larvae or other beneficial organisms in the tank. These treatments may include specific medications or natural remedies.

It is important to note that specific recommendations and approaches may vary depending on the specific species of shrimp, local conditions, and available resources.

In addition, my published articles can be of interest to you

Technical Report Algae Strain Identification for Wastewater Treatment

https://www.researchgate.net/publication/303976897_Using_Microalgae_for_Treating_Wastewater?

Poster Reaction Energy: Fueling tomorrow

@all The green color in the shrimp larval rearing tank culture water is likely due to an overgrowth of microalgae, particularly Thalassiosira weissflogii. When the microalgae population increases, it can turn the water green.

To address the issue of excessive microalgae growth, you can take the following steps:

Regarding the Vorticella infestation, Vorticella is a type of ciliate protozoan that can attach to the shrimp larvae, causing harm and high mortality rates. To prevent or reduce Vorticella infestation, consider the following measures:

Consulting with aquaculture experts or professionals experienced in shrimp larval rearing may provide more specific guidance and recommendations based on your particular setup and requirements.