Anchor Worms (Lernaean spp.) are parasitic crustaceans commonly found in aquariums, particularly in Arowanas. These parasites have two main life stages that affect fish: the Copepodite stage (juvenile) and the Cyclopoid stage (adult female). The adult female bores into the skin, fins, or gills of the Arowana, embedding herself in the host tissue using an anterior anchor after mating. This results in visible worm-like threads on the fish’s body, with the female adult measuring around 9mm. Poor tank conditions and water quality often exacerbate the situation, leading to secondary infections, swelling, and inflammation at the infected site.
Behavioral changes such as rubbing against surfaces or sudden darting movements may signal the presence of Anchor Worms. They are typically introduced into aquariums via new fish or live feed, such as goldfish.
The optimal temperature range for Anchor Worm development is 26–28°C, making temperature control a key factor in managing their spread.
Prevention
1. Quarantine New Fish: Isolate any new fish before introducing them into your main tank. This reduces the chances of introducing Anchor Worms or other parasites.
2. Limit Live Feeds: Feeding your Arowana with live feeds, especially goldfish, can increase the risk of Anchor Worm infestation. Minimize live feed and, if used, treat the feeder tank with medications such as Ocean Free ‘0’ Anchor Worm & Fish Lice to mitigate parasite risks.
Treatment Method
If Anchor Worms have been detected, proper treatment is essential to safeguard your Arowana's health.
1. Medicate the Tank: Use Ocean Free ‘0’ Anchor Worm & Fish Lice according to the product's recommended dosage. This medication targets the parasite’s nervous system, leading to a color change in the worms from transparent to opaque white. After 2–3 days, the dead Anchor Worms will detach from the fish.
2. Water Changes: Perform a 30% water change every three days to maintain cleanliness in the tank. Continue medication and water changes for at least two weeks, even if the fish appears to have recovered, to ensure all Anchor Worms are eradicated.
3. Avoid Physical Removal: Although it may be tempting to manually remove the worms, this is not recommended. Physical removal can be stressful for the fish and often fails to completely eliminate the parasite.
Additional Notes
- Increase Oxygenation: During treatment, using an air pump to increase oxygen levels in the water can support the Arowana’s health.
- Monitor the Fish: After administering medication, closely observe your Arowana for signs of distress, such as heavy breathing or erratic behavior. If distress occurs, perform a 50% water change immediately, ensuring the fresh water is properly treated and dechlorinated.
Anchor Worms are a serious issue for Arowana keepers, but with vigilant care, preventative measures, and proper treatment, they can be effectively managed, ensuring your fish remains healthy and vibrant.