Vet Q & AMy marine fish died from ich. How do I prepare the tank for new fish?
Ich (Cryptocaryon) is an obligate parasite. This means it needs fish to survive. If your tank has no fish, continue to run the filter and tank empty for at least 6 weeks. You can increase temp to about 86 F to speed up the life cycle of the parasite. If your tank is not a reef tank and has no inverts, you can treat the tank with copper. Once treatment is complete, decrease temps to normal ranges. Continue to monitor salinity/chemistry.
Quarantine any new fish for at least 10 days in a bare bottomed, established tank to prevent re-introduction of parasites into the main tank.
Updated on September 24th, 2025