Beginners Guide to Acclimation and Quarantine

Your beautiful new display tank is up and ready for fish. You have come up with your stocking list and you are finally ready to buy your first fish but you aren’t confident on how to proceed. I am going to walk you through a basic acclimation and quarantine procedure. I want to throw in a disclaimer and I really can’t stress this enough. What I am proposing here is not a 100% foolproof quarantine protocol. This is structured to provide beginners a faster, simplified method that will help avoid most common issues if done correctly. If you are setting up a 180g+ system with $1000+ in fish I recommend much more advanced quarantine practices. This is geared toward the average new hobbyist to give them a high chance of success in keeping healthy fish.


Prior to ordering fish or going to my local fish store I want to make sure I am ready. This means I have my quarantine tank setup and filtration ready. My quarantine tank is a 10g system with a hood, heater, thermometer, powerhead, and an oversized HOB filter with only the biomedia and sponge. I also put a Seachem Ammonia Alert badge in the tank since most ammonia test kits don’t work if with copper.

I prefer to set the tank up at least 4 or 5 days in advance. I will call or email the vendor and find out what salinity the fish will be delivered in. I’ll use a combination of tank water and freshly mixed seawater to match. Once the water is up to temperature I’ll add some Biospira and a little frozen food for ammonia control.

I also want to be prepared to deal with anything I may encounter when the fish arrive. This is a sample of what I keep on hand all the time. If a fish is sick the last thing I need is the stress of a run to the LFS or waiting on a delivery from an online vendor. Prime is one of those products that is great to have for multiple uses. I treat all my fish prophylactically with copper so I always have Coppersafe on hand. I also have an API copper test set. Not all test sets work with all copper products so it is important to check to make sure you have the right one. Prazipro is another medicine that I am more likely to use than not before the fish get to my display tank. In case a fish has a bacterial infection I like to keep MetroPlex, KanaPlex, and Furan-2 on hand. The Focus is used to bind the medications to the food. There are other options and other brands that will work just fine, these are just the ones I prefer.


Many experts and suppliers recommend using drip acclimation and for some species of fish and inverts this is the only option. For most fish it isn’t my preferred method. It doesn’t matter to me if I pick up the fish in person or if I order them online, I will acclimate my fish the same way. As soon as I get them out of my cooler or the shipping container I will float the bags in my quarantine tank. This will begin the temperature acclimation process. If you have more bags than can be floated in your QT, try to keep them in the 75F-80F range until you are ready to match them to the quarantine system. Leaving them in the cooler or shipping contain may be the best option.

Once I have floated the bags for around 20 minutes it's time to do some testing.
Just because I think I know what salinity my fish are in there is only one way to know for sure and that is to test it. I will cut as small of a slit in the bag as possible to draw a sample of the shipping water.

Once I get my sample I will tape over the opening to prevent air exchange. This is especially important for shipped fish. As the fish consume oxygen in the water they release CO2 and Ammonia. Ammonia (NH3) is very toxic to fish but the buildup of CO2 in the shipping water is going to help us by lowering pH. At a lower pH the NH3 tends to shift toward Ammonium (NH4) which isn’t nearly as toxic. We want to trap as much of this CO2 in the water as possible at this point to prevent an increase in pH and converting the NH4 back to NH3.

I use my refractometer to measure the shipping water and compare it to my quarantine tank. I want them to match exactly if at all possible. I keep a gallon of very strong salt water solution and some RODI water to make raising and lower salinity easy. For my latest batch of fish I was told they would ship at 1.021 yet when I received them my test showed 1.017. Not a problem though, I just pulled some salt water out, added RODI, waited for the temperature to equalize and I was good to go. Before cutting the bag open I like to verify temperatures match which is where the digital thermometer comes in handy. A quick dip in the quarantine tank to check the tank and then I peel back the tape from my earlier slit to check the shipping water. If they are within a few tenths of a degree I am ready to move on and I consider my fish acclimated at this point even though they are still in the shipping water. Some people recommend matching pH. I don’t bother since the pH will rapidly change once the bag is cut open and is exposed to fresh air.

At this point, I am ready to get the fish out of the shipping water and into my quarantine tank. I know that the shipping water is high in ammonia and other waste. What I don’t know is what else is in that water which is a lesson I learned the hard way. I purchased fish that had been shipped in water that contained copper. I was still drip acclimating at the time so I added Prime to the water to neutralize the ammonia. Unfortunately, while Prime took care of the ammonia it also makes copper significantly more toxic. Those poor fish didn’t last 2 hours. To make sure nothing like this happens again I do my best to get rid of all of the shipping water. You never really know what is in it.

With the salinity and temperature matched, we are finally ready to put them into the quarantine tank. I set up a bucket with a large strainer on it right next to my quarantine tank. I find a strainer easier to use than a net and I don’t have to worry about fish with spines, like Foxface’s, getting stuck in it. Now that I am ready, I cut the top off the shipping bag and dump the fish and water into the strainer. I lift the strainer out of the bucket and slide the fish into the quarantine tank. I’ll repeat this process for all the fish I need to add that day. I use a 5 gallon bucket so it normally isn’t an issue, but I want to make sure the bottom of the strainer stays above the shipping water.

Early Care:

I feel it is very important to reduce the stress for new fish as much as possible. For the first day I will only light the tank with ambient light from the room. For some fish, I will never turn the tank lights on at all. This last group I just put through quarantine were Dispar Anthias. They are shallow water reef fish which are more comfortable in brighter lights. As prey, not predators, they associate dim lighting as time to hide which raises their stress. So for this group I left the lights on for 12 hours a day.

My biggest concern with new fish is to get them feeding. I want to try starting them with whatever it is I plan on feeding them when they get into my display tank. For me that consists of a high quality frozen fish food blend, frozen mysis, and sheet algae. If they don’t start eating by day 2 I will try whatever else it takes to get them to eat. I have yet to find a Tang that will eat algae from a clip as soon as they are introduced into my system. To train them to eat I will rubberband small pieces of algae to a PVC elbow. This has worked very well for me.


How I treat fish while in QT tends to vary based on the situation. I will normally try to not add any medications to the tank for at least the first 3 days. I want to give the fish time to adapt and adjust to feeding without introducing any new stresses. If I do see something during the first 3 days that causes concern I will adjust my treatments based on the situation. Assuming that all the fish look to be doing good after day 3, I will do a freshwater dip on each fish to check for flukes. As long as there are no indications of flukes, the fish are all eating, and none have white stringy poo then I will skip treating with Prazipro. If Prazipro is needed, I will treat at the recommended dose twice, 7 days apart. I will follow this with a 50% water change and running carbon in my HOB for a day or two.

At this point I am ready to begin treating with copper. I use Coppersafe with the API test kit. I find reading these test kits challenging since I never seem to actually see a color that is on the chart. Instead, I mix up 1 gallon of saltwater and add the recommended 1.8mL of Coppersafe. I test it with my API kit and this color becomes my new target. If future tests are lighter I know I need to add copper. If they are darker I need to dilute the copper a little. My 10g quarantine tank needs 18mL of Coppersafe to reach the proper therapeutic level. I slowly raise the copper level in my tank by adding 2mL of Coppersafe each morning and evening for 3 days. It is important to maintain this level of copper without interruption! Even a few minutes at lower copper will give parasites an opening! I maintain therapeutic copper levels for 14 days. It works well since I only get fish on weekends and this keeps things lined up for my personal schedule.

During this treatment I have another task to accomplish along with the copper treatment. I want to use this time to adjust my quarantine system to match my display tank. This latest group of fish was a little more challenging since they came in at 1.017 and I keep my display tank at 1.025. I don’t like to change my salinity by more than 0.001 per day so this was a long adjustment. To make it easier I mixed up a 4 gallons of saltwater in a dedicated and well marked bucket to 1.040. I then mixed in 7.5 mL of Coppersafe. Remember to add the copper to the makeup water prior to adding to the tank to make sure there is always have a therapeutic level of copper in the system. Every morning and evening I would add my RODI top off water (if needed), pull a cup or two of water out of the quarantine tank, and replace it with this higher salt mix. I started with smaller changes and increased the amount I pulled as the salinity in the quarantine tank got closer to the make up water. This was an easy way for me to raise salinity and maintain copper without daily mixing. Just make sure the bucket is clearly marked and dedicated for the QT system. It would be a disaster if this was used as makeup water in a display tank!

After the 14 days in copper and with the salinity in my quarantine tank matching my display tank, the fish are just about ready for their new home. Ideally, the next new home will be another clean quarantine tank where we can observe them for an additional two weeks but I realize it can be a challenge for some hobbyists to set up one QT system, let alone two. If you don’t have the second quarantine system available DO NOT transfer them into your display if you have any questions about their health such as if they are breathing heavy or have frayed fins. If there are any doubts you can keep them in the original quarantine system with therapeutic levels of copper for 30 days. At this point, instead of transferring the fish you, you can safely remove the copper and treat with any additional medications that may be need. I like to give at least 1 fish in the system another fresh water dip to check for flukes prior to the transfer.

Final Transfer:

It is finally time to move the fish into my display tank. I use my Apex to adjust the temperature of my display tank to match my quarantine tank to make it easy to do a straight transfer. Manual adjustments of the heaters may be necessary if a controller isn’t available. I take the bucket and strainer that I used when I added the fish to my quarantine tank and set it up in front of my display tank. I have a small container that hangs on the front of the tank which I fill with water from my display tank. I will pull the PVC elbows out of my quarantine tank and either use a net or a small strainer to catch the fish and put them into the container. I dump this container into the strainer as a final rinse to minimize transferring copper or other medications into my display tank. From the strainer, I put the fish into an acclimation box in my display tank. They will spend anywhere from 1 to 5 days in the acclimation box depending on the risk of aggression issues. All that’s left at this point is to open the lid to the box, let the fish out, and enjoy my display knowing that I have an excellent chance of avoiding any major disease outbreak in my system.

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About author
Steven Frick has spent much more time under the ocean than keeping a small piece of it. He got his start in the electrical field in the US Navy Nuclear Power program as an electricians mate. After 5 years of service on the submarine USS Henry M Jackson he finished his final 3+ years of service teaching electrical theory at the Knolls Atomic Power Laboratory. Currently, he runs the projects and maintenance for the power distribution system of one of largest electrical consuming heavy industrial companies in the Southeastern United States. He wrote his sites electrical safety policies and routinely acts as a consultant to other industrial facilities looking to improve their electrical safety programs. As someone who loves to both learn and teach, he has focused his attention on his newest hobby, reefing.

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