Lack of proper quarantine is one of the biggest reasons for failure in the hobby.

But now you can have a better chance of success with the knowledge I’m going to share in this post.

I’m pulling back the curtain today on one of the BEST kept fishkeeping secrets of all time…

So what are you waiting for?

Keep reading to find out!

What is a Proper Quarantine?


Quarantine is more than an isolation period.

(Unless you got your fish from a trusted breeder directly.)

For fish from pet stores, fairs and other places that don’t quarantine…

… It involves actually treating for all common diseases right off the get-go.

And completely.

There are some sellers out there who hit the fish with a few chemicals for a couple of weeks and call it done.

That’s not complete quarantine.

Many parasites have a longer lifecycle and can “outrun” shorter treatments, especially at a lower temperature.

This can lead to your “quarantined” fish coming down with an issue later and/or infecting your whole collection.


Here’s the way I recommend quarantining to be as thorough as possible.

My Complete Freshwater Quarantine Protocol

Different people have different quarantine methods.

This is the one that I have found works best for me for pet store/suspicious fish. (I have never lost a fish in quarantine while using this method!)

I’ve acquired many fish over the years, some have been quite sick when I received/rescued them.

This method never failed to bring them back to health. :)

That said:

Very weak, stressed, sickly or little fish may not make it through quarantine no matter what treatments you use. This is normal.

Sometimes everything they’ve been through is just too much.

Unless the fish comes to you with a confirmed, serious issue that is without question the immediate cause of poor health, I recommend starting with the following:

1. How to Set Up Your Quarantine Tank

Here are some tips for your quarantine tank itself:

  • Tank: The quarantine tank doesn’t have to be anything fancy, and it doesn’t have to follow the same stocking guidelines as your main tank.  It can be an old used tank you found at a thrift store. It can even be a Tupperware tub. Whatever you use, your quarantine tank ideally should be in a separate room to prevent particles from the water traveling through the air and getting into your other tanks. NEVER share equipment between your QT tank and your other tanks unless it is fully sterilized in between uses. And don’t forget to wash your hands well after interacting with your QT tank.
  • Filter or Airstone: In a best-case-scenario, you would use a filter totally pre-cycled with liquid ammonia to keep the water clean.  At the least, it should have an airstone to keep the water oxygenated and the water tested and changed frequently to keep it clean.
  • Light: It’s important to reduce stress as much as possible after everything your new fish have been through. You’ll want to turn off or reduce lights (if you have them) for the first 24 hours. Bright lights can really stress new fish in a new environment.  Your quarantine tank does not need to have its own light.
  • Plants: I highly recommend adding some live plants to your QT tank, preferably disposable ones as they may not survive the treatment phases to come. I use Hornwort for my QT tanks as it offers shelter (which greatly reduces new fish stress), supports probiotic bacteria and helps purify the water. As it grows like crazy I always have extra on hand for situations like these.

2. Immune system boost

Once your new fish is all settled in to its new hotel, it’s time to work on building up their immune system.

This will help them to deal with the stronger antiparasitic treatments to come and help prevent fish loss.

To do that, I alternate Microbe-Lift Artemiss and Microbe-Lift Herbtana every 12 hours for the first 4 days before using any harsher treatments.

These natural immune stimulants help repair damaged tissue and fend off pathogens, including parasites, bacteria and fungus.


A strong immune system is your fish’s most POWERFUL protection against disease.

3. Treat External Parasites, Bacteria & Fungus

It is now time to proceed to more aggressive pathogen punchers.

Use 4-5 treatments of MinnFinn. These treatments are administered every 48 hours.

It deals with all common fish diseases.

Goldfish and koi should have a double dose, whereas other fish should have the regular strength doses.

4. Follow up with salt.

Use .2% (7 grams per gallon) for tropical fish like Bettas. Use a stronger solution for goldfish of .5% (19 grams per gallon) for 2 weeks.

Salt should not be combined with ANY other treatments.

It also should be dissolved before adding it to the water.

You need to build up the salt concentration gradually in 3 separate doses added 12 hours apart each to avoid shocking the fish.

You can use non-iodized sea salt without any anticaking agents or additives, but I prefer to use Himalayan pink sea salt as it adds many beneficial trace minerals to the water for your fish to assist in healing.

5. Deworm Your Fish

Finally for the last 5 days it is time to tackle pesky internal parasites.

There’s more than one way you can do this…

You can feed Metroplex, Levimasole, Hexshield or 3% Epsom salt feed twice daily for 5 days to get rid of nasty intestinal worms and internal hexamita.

Personally I like the 3% Epsom salt feed option because it is the gentlest on the fish’s system.

Use 1 level tablespoon of Epsom Salt (15 grams) to 500 ML of distilled water. Use an eye dropper to add water to food until the food does not absorb any more. – recipe from The Truth About Goldfish

Excess magnesium is easily removed from the fish’s body and has no harmful short or long term effects.

Why Quarantine ALL Your New Fish?


All fish should be quarantined REGARDLESS of where you get them from.

Even if you get the healthiest, disease-free fish to start with, they’ve been through a lot. The fish just needs to rest up a bit before being introduced to the others.

Some breeders and importers quarantine for you and do it very well.

For fish that come from reliable sellers like these, quarantine is very simple.

Isolation for 4 weeks minimum.

Why 4 weeks?

It gives you time to address any issues that could pop up after the stress of shipping and ensure the fish is fully healthy before introducing them to the others.

Your new fish are also really weak and don’t have resistance to whatever pathogens may be in your main system with your other fish.

Those pathogens are things your existing fish may be used to living with just fine.

Suspicious Fish

But when your fish comes to you from the pet store – or even from many online retailers who don’t do this- you HAVE to assume they are sick and treat them as such.

Because the truth is…

… They probably will be if they aren’t already.

Maybe you’ve heard  somepeople say you should only treat fish like they are sick if you see signs of a problem.

Actually, if you do that – you’re automatically at a disadvantage.

Because goldfish can carry low levels of pathogens without showing any obvious signs of them.

(It takes a microscope to do that.)

By the time they actually start showing signs, many times IT’S TOO LATE. :(

You might succeed in battling back the parasites for a time and think victory is yours…

… Only to have your fish succumb to a lethal secondary bacterial infection.

Preventative care is the key to not being stuck in a situation where you are desperately trying shotgun treatments and endangering your entire collection in the process.

Take it from me:

One new fish can do a whole lot of damage in a very brief amount of time.

Nip potential issues in the bud early on in the game and you will save yourself a ton of stress, money and potentially heartache.

“Oh No, What if I Didn’t Quarantine and Just Added a New Fish with My Others?”

The new fish and all fish exposed to the new one should go through this protocol.

And the sooner you do it the better.

You’d be surprised how quickly a disease outbreak can sweep through your collection, practically overnight.

Starting treatment EARLY is key to avoiding a more dangerous situation.


Now that you know how to quarantine new fish, I hope this information helps you become a better pet owner.

Do you have any tips or tricks you use for quarantine?

Find this information useful?

Let me know what you think when you leave your comment below!