TIP from FNM: Quarantine Fish

Quarantine tanks are essential to preventing disease outbreaks in fish tanks. By having a quarantine tank as wells as knowing how to properly quarantine a new or sick fish, the tank community will be protected from contagious disease and harsh chemicals that are used sometimes to treat them. 

1. Obtain the necessary supplies

  • A quarantine tank does not need to be expensive or look pretty
  • Used tanks work great if they are clean or a basic 10 gallon tank would do
  • Particularly large fish require a tank big enough to comfortably house them for 14-21 days
  • Make sure the heater and filter are adequate for the size of tank

2. Prepare quarantine tank

  • Quarantine tanks do not use substrate (like gravel), so paint the outside bottom (not inside) of the tank black to give a sense of "bottom" for your fish. Clean everything with warm water, NOT with soap or other chemicals.
  • If you are making a quarantine tank "just in case", you can stop here and double check everything is clean and dust free when your are ready to use it.

3. Set up quarantine tank

  • Fill the quarantine tank with water from the main tank
  • Add the hiding places, filter, heater and aerator (either an airstone or air pump) and turn on everything on.
  • Test the chemical levels in the water and make sure nothing is out of balance.
  • Try to keep the quarantine tank at the same temperature as your main tank, as you will eventually be transferring fish between the two.
  • If your filter uses carbon, remove the carbon as it can lower the effectiveness of medications.

4. Cycle your filter

There are a few options for doing this: 

  • Run your filter in the main aquarium alongside the existing filter for two weeks
  • Put the media from the quarantine filter into the main filter for at least two weeks.
  • Keep the media in your main filter until you need it, but replace it after using it in your quarantine tank
  • You do not want to contaminate the other fishes in the main tank, so cycle new media next time you need to quarantine a fish

5. Transfer your fish

  • If the quarantine fish is from an established aquarium, net the fish and place it in the quarantine tank. Ensure that the water in the quarantine tank has the same water parameters and temperature as the water in the main tank.
  • If the parameters are different or are quarantining new fish, slowly acclimatise the fish to the water in the tank
  • Begin by floating the fish in the bag from the store for ten minutes to steady the water temperature
  • Next, add a small amount of tank water to the bag and wait another ten minutes. Repeat this step at least once.
  • Finally, transfer the fish using a net into the tank. The water in the bag should never enter the tank. 

6. For the fish

  • For the next two weeks, observe the fish closely for signs of illness
  • Feed only as much as they can eat in 2-5 minutes, once daily
  • Test the water daily and perform water changes as needed

7. Treat any illness

  • If a fish becomes sick, diagnose the illness, possibly with help from an aquarium expert, and decide on a treatment method.
  • Extend the quarantine at least two weeks from the time you start treatment, to ensure the fish returns to health and no additional problems arise.
  • Again, observe the fish and chemical levels closely during this time.
  • Keep the fish in quarantine for at least a week after it appears healthy again.

8. Transfer the fish to main tank

  • Once you are satisfied that your fish is healthy, he may join the rest of the fishes in the main tank
  • Use the slow transfer method again, as the chemistry in the quarantine tank is not going to be the same as your main tank after two weeks
  • Try not to mix any quarantine water into the main tank, as it may still contain medications.

9. Store the quarantine tank

  • If not adding any more fish, and fishes in the tank appear to be healthy, disassemble the tank and store it until required again.
  • Empty the water and wash everything with warm water (no soaps or chemicals!). Let it dry and store it in a safe and clean place.

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