Aquaculture plays a crucial role in meeting the global demand for protein. However, the sustainability and productivity of this sector are constantly threatened by parasitic infections. Among them, Argulus, commonly known as fish lice, is one of the most problematic ectoparasites affecting freshwater and ornamental fish worldwide. Argulus is a genus of crustacean parasites that attach to the skin, fins, and gills of fish, feeding on their blood and tissue fluids, causing Argulosis. In countries with intensive aquaculture practices, such as India, Bangladesh, and China, outbreaks of Argulus have been reported as one of the top reasons for reduced fish yields, particularly in carp culture.
Current Control Strategies:
Chemical Control
A series of chemicals with a problematic toxicity profile are well known in aquaculture, as they suffer from ectoparasitic infections. Organophosphates (e.g., trichlorfon, malathion, dichlorvos), lufenuron, emamectin benzoate, deltamethrin, sodium permanganate, formalin, diflubenzuron, etc., are commonly used chemicals for the control of Argulus infestation in fishes.
Mechanical Control
In addition to chemicals, physical methods such as shaking infested fish in nets to mechanically detach lice, along with egg removal through drying or substrate manipulation (e.g., bamboo-egg boards), help to reduce infestation pressure.
Biological Control
Biological control strategies utilize natural predator–prey relationships to manage ectoparasites like Argulus. In tropical aquaculture, fish such as Gambusia have been noted to feed on free-swimming Argulus larvae, while other small fish actively remove parasites from the skin of larger hosts.
Limitations of Current Control Strategies:
- Synthetic chemicals have been used to control this ectoparasite. However, they will have an impact on physiological changes, fish growth, and the balance of aquatic ecosystems because they can leave residues that can enter environmental components. The active ingredients are very difficult to decompose in nature, and resistance can occur in target parasites. In addition, it can cause residue accumulation in the body of the fish.
- Mechanical approaches are labor-intensive and not always sustainable.
- Though biological control methods are eco-friendly and reduce the reliance on chemicals, they come with several limitations. One major challenge is the seasonal effectiveness of cleaner species—fish like wrasse are less active during colder months, reducing their efficiency in parasite removal.
These limitations highlight the growing interest in exploring eco-friendly, sustainable, and effective natural alternatives to control this parasite.
Plant-Based Alternative to Control Argulosis:
Alternatives for controlling argulosis in fish farming can use medicinal ingredients derived from herbal plants. Pharmacologically, these herbs have therapeutic effects as antibacterials, antiparasitics, and immunostimulants. Numerous applications of medicinal plants as alternative medicine for treating Argulosis in fish have been carried out. The ability of plants to control this disease is due to the presence of natural products in the form of chemical compounds in organic form, so they are safe to use and do not pose a risk that is harmful to fish, to humans who consume them or to the environment and do not cause resistance to parasites.
Dehook is a natural solution for relieving Argulus infestation in aquatic animals, offering a safe and eco-friendly alternative to chemical treatments. Know more about Dehook at Vinayak Ingredients (India) Private Limited.