Saltwater Quarantine Tank – A Complete How To Guide

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To Quarantine or Not To Quarantine – that is the question. This topic comes about with confusion and complexity because many new hobbyists do not know how to setup a proper saltwater quarantine tank. Today’s post is all about why we Quarantine and the various methods. See the video below and if you would rather read along, I have the post below for your reference.

Key Takeaways

  • Fish diseases are worse in saltwater fish with three being potential tank wipers – Marine Velvet, Brook, and Uroema
  • Probalaytic Quarantine is more common and accepted in marine fish vs freshwater fish
  • There are multiple methods you and use to quarantine fish – all with pros and cons

Why Do We Quarantine Our Fish?

I’m going to go off the cuff here and say that the primary reason for quarantine is recovery of your fish. Fish that you have picked up to from the local fish store or online have gone through a variety of channels to get to you. It is probably an understatement to say that if the fish has come to you and is wild caught it is within the top 25% of fish in the supply chain that made it out. Many fish die or get sick during capture and transplant.

The Ornamental Fish Trade Supply Chain

Quarantining a fish allows the fish to destress and for you to have the fish adjust to your parameters, your food, and provides it a safe space for it to thrive away from more aggressive and established tank mates who can out compete it for food. Putting a fish directly into your display puts the fish in more stress and added stress events leads to our next reason for why we quarantine our fish.

Preventing Saltwater Fish Diseases Through Quarantine

A fish’s immune system should be able to fight off more infections and diseases, however the shock of transportation compromises your fish’s immune system leaving it vulnerable to any disease that gets shipped with it. Some of these diseases when they break out can be so deadly, they can wipe out your tank within days. So what are these deadly diseases? Well, I will tell you right now it’s not ich. Ich is child’s play compared to these three and they are becoming more and more common in the fish supply chain.

Three Deadly Fish Diseases

When you look up diseases, forum posts, or YouTube videos online you will come to MANY articles about ich. Ich this and Ich that. Now Ich is common and can kill your fish, but can be treated and in some cases your fish can simply recover from it. But these three diseases are 100% deadly, will wipe out your tank in days, and there are no known ways to treat these diseases with reef-safe medications (Sorry Kick Ich, Ich Attack, Ich Guard, Paraguard — this ain’t working on them).

Marine Velvet 

Marine Velvet

It’s the most common saltwater fish disease of the Deadly Three. It looks like ich, but it is far more deadly. Sometimes it kills fish before they are even able to display symptoms. Marine Velvet MUST be treated in a quarantine tank/hospital tank and requires your main display to go fishless for 76 days to remove it from the display. It is probably the #2 reason for tank crashes in the hobby with heater failures being #1. The go-to treatments are Copper or Chloroquine Phosphate.


Uromea Marinum

The least common of the deadly 3 but considered the worst and hardest to treat. Chromis and Anthias are unfortunately the most prone to this disease, but it can spread to other fish. This particular disease is resistant to Copper and Choloroquine Phosphate, requiring higher than traditional dosages. It can also go into the internals of the fish and damage it further requiring other medication like Metro to add in internal treatment. Uroema is also a free living parasite which means it can exist without fish present in the tank. Once a fish has Uroema one should assume that the disease exists in the system. Talk about scary!

Brooklynella (AKA Clownfish Disease)

Brooklynella Clownfish Disease

Brooklynella is a nasty disease that Clownfish and Anthias are unfortunately prone to. This is how it got it’s infamous nickname of Clownfish Disease. Brooklynella looks similar to velvet, which in my opinion is why it is safe safe to assume that your fish has either or when you observe it. Both Brooklynella and Marine Velvet can be treated with Copper and Chloroquine Phosphate. Further protection with Metro is recommended to protect the internals of the fish as Brooklynella can also go internal as well.

How To Isolate Fish – The Various Methods

So now we have discussed why we quarantine fish, now let’s discuss the types of QT and rate each one.

Deciding Not To Isolate

No QT Tank

All the power to you if you want to go this route. The hobbyists most successful with this method have stellar local fish stores (LFS) around them that they have strong relationships. If the store can hold a fish for you for 2-4 weeks, you will have better success. However, finding a local fish store this stellar for most of us is a needle in a haystack. Personally, in my location I have had difficulty finding a good local fish store. Literally every fish I have purchase came with something and QT has saved me tons of headache and thousands of dollars in losses.



Hyposalinity has been around for ages in the hobby. It’s a tried and method that requires precision and constant monitoring. The reason why it doesn’t make my list of preferred methods is because it will not treat against the Deadly Three. This disqualifies this method for me.

Tank Transfer Method (TTM)

Tank Transfer Method

Tank Transfer Method or TTM is a very popular method among the forums and even by some online store who have suggested it as a reliable method. However, the supply chain has changed since those times. 3 years ago I would say TTM was great, but with the increased commercialization of the hobby I am seeing more and more of the deadly 3 appearing and cannot recommend this method any longer. Tank transfer method will not protect your fish against the deadly three. You can however do a hybrid TTM with medications like Copper and CP, which I will explain in Part 2.

Safety Stop

Safety Stop

Now we are getting to methods that protect against the deadly three (Amazon Affiliate links ahead). Safety Stop is first up (Ruby Reef Rally can also be used if you cannot obtain Safety Stop). Safety Stop is a medicated dip of Formalin and Methylene Blue. Formalin is consider one of the hard drugs of the hobby, capable of wiping out various disease such as Marine Velvet, Brook, and Uroema.

Melev’s Reef has documented his process of how he added all his fish to his 400 Gallon tank with no quarantine over a 2 year period. That is proof that this method will work. Safety Stop will not prevent against internal parasite however and if your fish end up with a bacterial infection – there is no way to treat this in a display. This is why I recommend dipping your fish in Safety Stop before they go into Quarantine

Copper – (Using Chelated Copper AKA Copper Power)

Chelated Copper Coppersafe

Time to get into the good stuff! The next two method are ironclad and will protect against just about any disease in QT. The next two methods also have their uses depending on the fish you needing to QT. Chelated copper is considered more preferable over over type of copper because it is safe and has a higher therapeutic range. You have to maintain your levels throughout the process and I would recommend a precise tester like a Hanna Checker.

People are generally scared of copper due to the fears from Companies selling “Reef Safe” medication and those who want to do natural remedies. I will tell you right now that both Copper and Chloroquine Phosphate are veterinarian choices when it comes to treating external parasites. Would you rather listen to a licensed vet or a Company that wants to make money off you selling subpar medication?

*UPDATE* – We no longer support Copper Safe for Chelated Copper. Copper Power would be the safest and more consistent chelated copper on the market. Use together with a Hanna Checker Copper Tester. Copper Power is very difficult to find at a local fish store. It is best to purchase it off Amazon directly from the manufacturer, Enrich. Copper can also be combined with General Cure instead of Prazipro.

My Pick
Copper Power

The Most Available Velvet Mediciation

Copper Power is Chelated Copper that is more stable than Cupermine and easier to use

Buy On Amazon

Here’s a video from my friend Aaron who goes over Copper Power treatment. You can use this Copper Power Calculator to determine the dosage you need:

Chloroquine Phosphate + General Cure (The Current Meta In Marine Fish Disease Treatment)

Chloroquine Phosphate

We have come to the pinnacle of Prophylactic treatments available in the hobby. Chloroquine Phosphate plus the combination of API General Cure is provides the simplest nearly full proof method of quarantine. Chloroquine Phosphate (or CP for short) is the preferred medication for Marine Velvet, Brooklynella, and Uroema. It is as close to a wonder drug as you can get currently. It is easy to administrator as long as you have a good digital scale to measure (these are easy obtained for cheap).

The main issue with Chloroquine Phosphate is that is it difficult to obtain outside of a Veterinarian’s prescription. If you are like me, you probably cannot obtain Chloroquine Phosphate from a Vet and have to go of the route of obtaining it from a supplier. Getting it from a supplier can be risky as you may not know the source and the purity of the substance. I obtain aquaculture grade Chloroquine Phosphate so you can always purchase it from me and I have certificate of analysis available so you know the purity and can adjust accordingly. Here is a link to a Chloroquine Phosphate Dosage Calculator.

Instructions for Setup

Setting up a quarantine tank is fairly easy to do, you just want to make sure you have the correct equipment and meds to get started. You will want to start off with a long tank. A 20 gallon or 29 gallon are ideal as you can use this larger quarantine tank to house multiple fish and get your QT done faster. A 10 gallon tank will also suffice, but more suited to 1 fish at a time quarantine. Petco’s dollar per gallon sale is the way to go to get these tanks as they are really cheap if you buy them on sale.

After that, you want a reliable power head for flow – at least 400 gph and some type of filtration. I prefer to use the best power filter, which is an aquaclear power filter as you can use multiple media in the filter and use carbon to remove medication. A sponge filter is also an ideal alternative for a budget conscious build.

A seachem ammonia badge is necessary to monitor your ammonia levels since many low priced test kits will not detect ammonia correctly once you start doing copper or chloroquine phosphate.

A heater (check out our best aquarium heaters post for recommendations) and a cheap thermometer round out the list of electronic equipment.

The last things are shelter and a cover. PVC fittings are ideal because they will not absorb medication and can provide tunnels for your fish. These can be purchased from any hardware store. A cover is an absolute must if you want to provide a fish from jumping. I prefer a glass cover for QT systems since I don’t have to worry about evaporation and can be custom cut in the back to ensure 100% coverage.

Getting a QT tank cycled up can be a tricky endeavor. If you are starting brand new, the best way to quickly cycle the QT tank is to throw in a few of the filter sponges in your dry or live rock tank when you start cycling your main tank. Once that tank cycles, the media in the tank will be full of bacteria and ready to go into your QT. If you started with dry rock, you have the advantage of starting disease free so you can freely throw in the sponges in the QT system to get started.

For live rock starts, if you follow the proper “cooking” method of no lights and a 5-8 week cure, that period of time going fishless should eliminate all harmful pathogens in the water column. Since you are going to use meds in your QT, the risk is pretty minimal so as long as you follow a 5-8 week fishless cure timeframe with liverock you will be ready to go with your QT system. The advantage you have with liverock is that the rock can self-sustain without fish indefinitely so you can take your time QTing. With dry rock, you will need to monitor your phosphates and nitrates to make sure you do not bottom out.

If you already have a tank setup, throw in the filter sponges in your sump for 2-3 weeks to get it full of bacteria. You do run the risk of introducing pathogens if you didn’t QT previously. Another method is to dose the sponges with bacteria-in-a-bottle products like biospira and carefully monitor your ammonia levels from there.

The video above goes over the parts list and the complete 32-35 day flowchart for quarantine with CP and General Cure. Both the method I use and Aaron’s will work very well so use the method that works for you and with the medications you can obtain.

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    • Hi Darren. Thank you for your comment. Bacterial infections are quickly turning my deadly 3 into the 4 horsemen of marine diseases. I cover bacterial infections in my marine fish diseases post. I don’t really pre-treat bacterial infections. I tend to treat the if I see them. I don’t even believe the be QT pros like Humblefish even pre-treats bacterial infections at this time.

    • Hi Aaron. That unfortunate to hear. You can try SeaChem Metro and Prazipro. Metro and Prazipro would be dosed separate so it would extend your QT a bit more.

  1. Hi Dinesh,

    Due to COVID, all CP related products are no longer available from aquaculture facilities (they all stopped carrying because humans were talking it). The only way to obtain them now is either through a Vet or from a lab. You would need to be a researcher or have an aquaculture license to get CP from a lab. It can’t be used in a display like Copper can in fish only tanks.

    Thank you for your comment. I made this video and blog because I was frustrated with the lack of information online. Many bloggers and companies don’t want to touch the subject with a 10 foot pole because they are afraid of liability. I just want to share good information to my readers.

  2. Hi, how much does the aquaculture grade Chloroquine Phosphate cost? Also, does it have a shelf-life, want to keep it for safety. I only treat with Copper safe and Prazipro in my display. Will CP wipe out the nitrifying bacteria in my tank if I need to use it? This is the best quarantine article I have ever seen, and I’ve seen most online.



  3. Hi Ginger,

    That would not work. The diseases would spread within you tank if the newly introduced fish is added and they had something. The best practice is a separate quarantine tank that is at least 10 feet away from the main tank. This is to prevent cross contamination between both tanks.


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