Acclimating Saltwater Fish in 10 Easy Steps

Drip acclimation is an easy technique to help minimize stress for new specimens

Drip acclimation is an easy technique to help minimize stress for new specimens

Contrary to popular misconception, introducing a new fish to a saltwater aquarium is not a simple matter of floating the shipping bag in the tank for 15 or 20 minutes and then releasing the fish into its new home. Sure, this step may equalize the temperature of the water in the bag with that of the aquarium, but it does nothing to address specific gravity, pH, or other important water chemistry values.

To ensure your fine, finned friend has a chance to adjust with minimal stress to the water conditions in your system—which are almost assuredly different in some significant way from those in your dealer’s tanks—it’s important to acclimate it to your water gradually and methodically.

This can be achieved using several different acclimation techniques. The one we’ll discuss here is a form of drip acclimation that can be completed in 10 easy steps using materials you probably already have on hand. You can use this technique any time you’re putting a new fish in quarantine or transferring a quarantined specimen to your display tank.

Here’s what you’ll need:

  • A clean plastic or glass container (large enough to hold at least twice the volume of water your fish came in but not so wide across the bottom that the fish won’t be fully submerged in the shipping water alone)
  • Several feet of flexible airline tubing
  • An adjustable flow-control valve or clamp designed to fit the tubing
  • A clean, dry cloth or towel
  • A supply of clean salt water

Here’s how it’s done:


Ensure the airline tubing is long enough to extend from the aquarium down to your acclimation container with length to spare. Attach the flow-control valve or clamp to one end of the tubing. If you don’t have a flow-control valve or clamp, a simple alternative is to tie two or three loose knots along the length of the tubing.


Place the acclimation container below the level of the tank, and position the airline tubing so one end is submerged several inches below the water surface in the aquarium (you’ll need to clamp the tubing to the rim of the tank or wedge it between the tank rim and cover to hold it in place) and the end with the flow-control valve/clamp is suspended just above the acclimation vessel. If you use the knot method, it doesn’t matter which end is up.


Very gently pour the fish and shipping water from the bag into the acclimation container.


Start water flowing through the tubing by placing the open end into the effluent of a powerhead or filter return nozzle.


Quickly adjust the flow to a steady drip—approximately two or three drips per second—using the flow-control valve/clamp or by tightening/loosening the knots.


Drape the towel or cloth over the top of the container (loosely so you can easily pull it back to monitor progress) to help calm the specimen and prevent it from jumping out.


Allow the water to drip until the volume in the acclimation container doubles.


Drain off and discard half the water in the acclimation container (I use a clean turkey baster for this purpose), and resume dripping.


Once the water volume in the acclimation container doubles again, test the water parameters. If the specific gravity, pH, and temperature values aren’t identical to those in the aquarium or quarantine tank, continue dripping, draining, and testing until they are. At that point, it’s safe to go ahead and transfer the fish to its new home.


Top off your quarantine system or display tank with clean salt water to replace the water lost during the drip-acclimation procedure.


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Matt Bowers (Muttley000) says

    It is worth noting, and maybe a topic for a future post, that dripping can be a problem for long bagged specimens. If shipped from an online vendor for instance, a different procedure should be used to keep ammonia from becoming more toxic as ph rises.

    • Jeff Kurtz says

      That’s an excellent point, Matt. I guess I tipped my hand and revealed a certain bias for purchasing livestock locally by starting with the drip method (he he!). Definitely keep an eye out for future posts on alternative acclimation methods!

      • My favorite thing about this site is probably the fact that even though you guys are all professionals, sometimes even you forget simple details. And there is absolutely nothing wrong with that. You guys don’t get defensive when a commenter adds something.

        It isn’t a matter if lack of knowledge or bad information, its just human to sometimes forget specific details. I work at a LFS and as much as I try to explain everything, you can only cover so much in a 10 minute conversation. Plus sometimes I just get too overzealous and excited about the customers purchase. =)

        I don’t drip unless it’s a super sensitive (or expensive) specimen. I usually use Paul’s method. I place the fish in a specimen container in the tank so temp equalizes. I then add tank water with a baster every 15 minutes for about 40 minutes. Seems to work out fine so far.

        • Thanks so much for your kind remarks and insights on acclimation! We’re definitely trying to create an environment where everyone’s input is valued and no one feels foolish for asking questions or admitting mistakes. In our years in the hobby, Chris and I have made so many errors between the two of us that we could probably write a book on the subject (though there are some I’ll probably never admit to or will only acknowledge under an assumed name!).

          • I definitely appreciate that. Sometimes we don’t want to ask “silly” questions cause we get “silly” looks (or responses) as if we should have already known the answer.

  2. I am not a fanatic with many things in a reef but I do always check the salinity of the water in the bag with a specimin I bought. I also don’t use the drip method but that is the best method. I just squirt some water from my tank into the store water with the specimin. I keep doing that every few minutes until the salinity, and temperature is the same. If the salinity of the specimin water and my tank are the same, my acclimation only takes a few minutes. If it is way off, it may take me an hour or two to acclimate an animal. I have never lost a creature during acclimation. If you are going to quarantine, then you have plenty of time and can acclimate as long as you like. I also like to cover the container the fish is acclimating in just to darken it so the fish doesn’t get spooked, especially if he notices one of the Supermodels that are always in my house helping me take care of the fish. Oh wait, that was a dream

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