How Do I Acclimate My Fish, Corals, and Invertebrates?

Acclimation Guide

Acclimation Guide

Please read this Acclimation Guide in its entirety before attempting to acclimate your new livestock. Acclimation is the process of helping an animal gently adjust to changes in its environment, such as changes in lighting, water temperature, salinity, and pH. Fish, invertebrates, and coral are very sensitive to even minor changes in these parameters, so acclimation is important.

NOTE: Our fish ship at an SQ of 1.017 to 1.020 and coral ships at an SQ of 1.021 to 1.023, you should be prepared for this.

The marine life you are receiving has just endured a stressful journey in total darkness. By taking the time to read the Acclimation Guide and acclimate them properly, you will help ensure that the transition to your tank goes successfully. We recommend the Drip Method for acclimation, which is detailed below.

IMPORTANT: After you have received your shipment, be sure dim the lights in the room where you will open the box, turn off your aquarium lights, and wash your hands thoroughly. BE PATIENT, this process can seem tedious but is very important for the health of your livestock and tank. Follow the Acclimation Guide and acclimate everything! Many animals are severely stressed during transport, and may even appear dead; many times they will revive if properly acclimated. Please see section below about “Common Behaviors During Acclimation.”

FISH & INVERTEBRATES (except snails and crabs)

  1. After you have opened the box (in a dimly lit room), check to make sure that the bags are intact and that you have received everything you ordered. Do not open the bags yet. Separate the fish, corals, and inverts into groups because each group will be acclimated separately.
  2. Place the sealed bag(s) in your aquarium; they will float on the top. They should be left to float for 30 to 45 minutes to allow the temperature to equalize.
  3. Prepare a sterile container for the acclimation process – you can use a bowl, bucket or even the Styrofoam insert that your livestock was shipped in. If you are using a bowl or bucket, it is very important that it has been rinsed thoroughly of ALL soaps or chemicals.
  4. Place your fish bags in the empty acclimation container. For each of the bags, cut open the top and gently empty the water and fish into the container. Your fish must be submerged in water, so if water is shallow, tilt one side of the container to make one side deeper and the fish is submerged. Repeat this process for all of the bags with fish. You should not fill the container more than halfway with water as you will be doubling the amount of water during the drip acclimation process. Depending on how many fish you have received and the size of your container, you may need multiple containers. If your container is shallow, you might need to cover it to prevent fish from jumping out.
  5. Prepare you drip line. Attach a drip line tube to the top or front of the aquarium so that one end is submerged in the aquarium water.  Tie two loose knots somewhere in the middle of the tubing. This will help control the amount of flow by tightening/loosening. Start a siphon by sucking on the non-submerged end of the tube. Adjust the knots looser or tighter to achieve the desired flow of 2-4 drops per second. It is better to fill too slowly than too fast.
  6. When the water volume in the bucket doubles, discard half and begin the drip again until the volume doubles once more – about one hour.
  7. You can now gently transfer the fish to your tank, one at a time, using a fish net or sterile cup.

INVERTEBRATES (snails & crabs)

  1. Begin with Steps 1–3 of the Fish Acclimation Process above to acclimate water temperature.
  2. These animals ship in much less water and are therefore easily acclimated either in their original bag or in a sterile container as described above. If acclimate them in the bag, simply open the bag to allow water from your drip line to be added and then secure the bag so it doesn’t tip over as more water is added.
  3. Depending on the animals, sometimes they will only be shipped with newspaper or paper towel to keep them moist. Create a drip volume that adds maybe one drop or less per second (see above). This should create about an inch of water over a period of one hour. For these creatures slower truly is better.
  4. After one hour, you can simply add the animals to the sand bed by hand (do not put acclimation water into the tank).*** Sponges, clams, scallops, and gorgonians should never be directly exposed to air. Follow the acclimation procedure, but instead of netting the specimen out of the shipping bag, submerge the bag underwater in the aquarium and remove the marine life from the bag. Seal off the shipping bag underwater by twisting the opening, and remove it from the aquarium. Discard both the shipping bag and the enclosed water. A tiny amount of the diluted shipping water will escape into the aquarium. Do not be alarmed; this will have no adverse effect on the tank inhabitants.


  1. Begin with Steps 1–3 of the Fish Acclimation Process above to acclimate water temperature.
  2. Remove your corals and place them in the empty acclimation container. Depending on how many corals you have received and the size of your container, you may need multiple containers.
  3. Add approximately ½ cup of water about every five minutes or so. Once the container has become full, remove and discard about half the water from the container and continue adding water from your tank to this container. Repeat this about three times or until you have replaced all of the water from the store with water from your tank.
  4. As you are adding water from your tank, watch carefully for any hitchhikers that may have been hiding in the coral and remove them.
  5. Pest Coral Dips (Optional) – While not everyone performs coral dips, they can be helpful. This process helps prevent potential parasites or hitchhikers, such as unwanted crabs, flatworms or nudibranch from sneaking into your tank. Whatever coral treatment dip you choose, be sure to follow the instructions on the bottle. If I see any harmful SPS crabs, manually remove them as some are very hardy and can survive the coral treatment dip.
  6. We recommend using sterile rubber gloves because some people are allergic to the toxins coral release. This also prevents you from being stung by certain corals. You can now add the corals to your tank. Find a good location where the new coral will receive the appropriate flow and lower light. It will need a few days to adjust to the new lighting and conditions.

Common Behaviors During Acclimation

  • Fish: They may breathe heavily and will sometimes lose coloration or lie on their side for a while (wrasses are known to play dead as a defense mechanism, continue with full acclimation.)
  • Snails & Crabs: They may not move for a couple of days, give them a bit of time. You can inspect them for movement. If they have a foul odor, they are dead and should be disposed of.
  • Corals & Anemones: When moved, they will often retract, lose colors and shrink and it may take days for them to return to their normal state.
  • Starfish: They may not move for several hours. If you think they are dead, you can pick them up and check for signs of death such as disintegration or decay.

A Note on Quarantine Tanks

Every attempt has been made to ensure that the marine life you receive is disease-free. Although we do not require the use of quarantine tanks for our Livestock Guarantee, we do recommend them for a number of reasons. Adding new livestock to a quarantine tank first reduces the possibility of introducing disease and parasites into your aquarium. Even if a new fish is technically compatible with the existing fish in your tank, it may still get bullied (please see our Compatibility Chart.) Some fish will pick on new arrivals that are weaker or smaller causing stress and even death. Quarantine tanks must contain the same water parameters as your community tank.

Important Facts

Choose livestock carefully! Animals which show signs of physical abuse or damage due to harassment are not covered by our Livestock Guarantee.

Never place an airstone into the shipping bag when acclimating your new arrival. This will increase the pH of the shipping water too quickly and expose your new arrival to lethal ammonia.

Leave your aquarium lights off for at least 4 hours after the new arrival is introduced into the aquarium.

Most invertebrates and marine plants are sensitive to salinity changes. It is imperative to acclimate invertebrates to a specific gravity of 1.023-1.025 or severe stress or trauma may result.

Our fish will come with an SG of 1.017 – 1.020.

Our Coral will come with an SG of 1.021 – 1.023