Leeches
Hirudinea
Moderate severity ⚠️ Contagious
blood-feeding parasites usually introduced with wild-caught fish or pond plants
Symptoms
Catching illness early gives the best chance of recovery, so check your fish daily. Visible worm-like parasites attached to the skin or fins, anaemia (pale gills) in heavy infestations, irritation and weight loss. Act promptly if you see several signs together.
Causes
Aquatic leeches introduced with wild-caught fish, pond plants or live food; they attach and feed on the fish's blood. The underlying trigger is almost always stress, poor water quality or a newly introduced animal.
Treatment
Remove visible leeches carefully (a salt bath can make them detach), then treat the tank and remove any intermediate hosts (snails). Quarantine and inspect all new arrivals.
While treating, increase aeration, remove activated carbon from the filter, finish the full course even after symptoms fade, and keep the water immaculate. Marine treatments belong in a separate quarantine tank, never the reef.
Prevention
Quarantine and inspect wild-caught fish and pond plants, and avoid introducing untreated live food. The golden rules: quarantine new arrivals, never overstock or overfeed, avoid sudden swings, and keep up regular water changes.
FAQ
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This information is general guidance, not veterinary advice. Consult an aquatic vet for serious cases.