A Simple Guide on Acclimation of Fish and Coral

Acclimation is one of the most misunderstood processes in the aquatic life industry. Sure, many people are familiar with acclimation and may have some idea of what it entails, however, many don’t know the exact process to follow. This issue, unfortunately, is leaving many fish or corals unable to survive in new tanks which leaves many people very confused and frustrated.

We are going to explain the importance of acclimation for all aquatic life. We will also provide you with a quick break down of how to go about this process correctly to put an end to this frustration once and for all!

Acclimation of Fish in Tank
Acclimation of Fish and Coral


What is acclimation and why is it important?

When you purchase a fish or corals from a pet shop or aquarium, the water that they are packaged in is very different to the water you would have prepared for them in your home tank. In most cases, everything is different; the pH levels, salinity parameters, and temperature. Why does this matter? You guessed it! Fish and corals (especially invertebrates) are very sensitive to environmental changes, so much so that a slight change in any of these elements means life or death. In some cases, the water at the aquarium you purchase the fish or coral from is toxic. In summary, proper acclimation is key to ensuring their successful relocation and survival.

What is the process of acclimation?

Now that we have made the importance of acclimation pretty clear, let’s get straight to the point; the process of acclimation. There are two methods to choose from when acclimatizing your fish/coral to their new environment. Before starting there are a few things to do note prior to starting:

1. Do not rush the process! – Although it may seem tempting to find shortcuts in the acclimation process, as mentioned, the survival of your new fish/coral depends on this process, so it’s worth taking your time.

2. Start with your aquarium lights off – As mentioned all environmental factors count, so keep your aquarium lights off at the start of the process and for at least four hours after the specimens are introduced to the aquarium.

3. Quarantine Tanks – We highly recommend their use to reduce the possibility of introducing disease and parasites into your aquarium. Click here out if you’re fish and/or coral are suitable for a quarantine tank.

Method 1: Floating Method

  1. Turn off aquarium lights.
  2. Dim the lights in the room where the shipping box will be opened. Never open the box in bright light – severe stress or trauma may result from sudden exposure to bright light.
  3. Float the sealed bag in the aquarium for 15 minutes (without opening the bag)This step allows the water in the shipping bag to adjust slowly to the temperature in the aquarium.
  4. After floating the sealed shipping bag for 15 minutes, cut open the bag just under the metal clip and roll the top edge of the bag down one inch to create an air pocket within the lip of the bag. This will enable the bag to float on the surface of the water. Note: For heavy pieces of live coral that will naturally sink, place the bag containing the coral in a plastic bowl or specimen container.
  5. Add 1/2 cup of aquarium water to the shipping bag.
  6. Repeat step 5 every four minutes until the shipping bag is full.
  7. Lift the shipping bag from the aquarium and discard half the water from the bag.
  8. Float the shipping bag in the aquarium again and proceed to add 1/2 cup of aquarium water to the shipping bag every 4 minutes until the bag is full.
  9. Net aquatic life from the shipping bag and release into the aquarium.
  10. Remove the filled shipping bag from the aquarium and discard the water. Never release shipping water directly into the aquarium.

Method 2: Drip Method

The Aquatic Live Food Acclimation Kit is a convenient alternative that simplifies the Drip Acclimation method.

  1. Turn off aquarium lights.
  2. Separate fish inverts, and corals into their own groups. (Never acclimate any of these 3 groups in the same body of water)
  3. Float as many bags that can comfortably fit in your aquarium for 15-20 min. This will bring the temperature of the water in the bag to what the tank is. 
  4. The  Styrofoam box sent with your order makes a great sterile acclimation container and never gets confused as a cleaning bucket. If a bucket is used make sure it is 100% sterile. Remove the first group and place them into the foam box. Cut open the tops of each bag and empty water gently into the foam box.  (Note: You may need to prop up one side, in the beginning, to allow water to submerge the fish/coral.)
  5. Repeat process for all. The level of the water should be no more than halfway up the box-if it is, split up the acclimation into multiple boxes. TIP: If possible, cover the top with something so that fish don’t jump out and to reduce light. 
  6. Prepare your drip line by sticking the suction cup on the top or front of the aquarium so that one end is submerged. Then tie the two loose knots somewhere in the middle of the tubing.
  7. Begin a siphon by sucking on the end you will be placed into one of the foam boxes. Start with tight knots, then loosen slowly to achieve desired flow (2-4 drops per second). The water volume in the foam box should double in 30-60 minutes.
  8. Once water volume doubles, discard half the water from the box and then repeat the process 2-3 times. 
  9. Net one fish at a time to prevent scratches or wounds, place gently get into the tank. Corals & Anemones-  gently place into the tank using sterile gloves.