Flukes are flatworm parasites that attach to fish gills (gill flukes) or body surface (skin/body flukes). Common on wild-caught marine fish and in inadequately quarantined freshwater systems. Symptoms: rapid breathing, scratching, flashing, mucus production.
Causative organism: Monogenean trematodes
Severity: Moderate to severe
Gill flukes attach to gill filaments (rapid breathing primary symptom). Body flukes attach to skin/scales (visible in extreme cases as 1-2mm transparent worms). Both treat the same way.
PraziPro, Hikari Prazipro, or pure Praziquantel powder. Dose to 5-10 mg per liter of system water. Unlike copper, Prazi is reef-safe and freshwater-safe.
Maintain Prazi concentration for 5-7 days. Some flukes have eggs that hatch over the treatment period; the medication kills hatchlings as they emerge.
Wait 7-10 days, then repeat the 5-7 day treatment cycle. Prazi doesn't kill eggs, so a second cycle catches any hatchlings that emerged after the first treatment ended.
After both treatment cycles, run fresh activated carbon for 24-48 hours to fully remove Praziquantel from the system.
Gill and Body Flukes is preventable in 95%+ of cases by running a 4-6 week quarantine on every new fish before introduction. Read the quarantine protocol.