The world’s coral reefs are one of the most stable environments on the planet.  The animals we keep in our reef aquariums are not adapted for sudden changes in water temperature or chemistry.  The process of slowly introducing an animal into it’s new environment is call acclimation or acclimatization.  Many reef animals will need special consideration when introducing them to your aquarium.  Research any new addition before purchasing or adding to your system.


New additions can bring disease to your aquarium.. Even the best stores and wholesalers encounter disease and parasites.  A coral frag or fish from your friend’s tank presents the same risks. It is up to you to minimize the risk and protect your investment by quarantining all new additions in a properly setup quarantine tank for at least 3 weeks.  Observe the new specimen carefully.

Simplified Fish Acclimatization

  1. Turn off the aquarium lights.  This is to reduce stress on the new arrival and to prevent the water in the transport bag from overheating.
  2. Float the bag or container with your new arrival in the aquarium for 5 minutes.
  3. Open the bag and add one half cup of aquarium water to the bag.  Reseal the bag or roll the edges down to trap air and keep the bag floating.
  4. Every 5 minutes, add another half cup of water until you have doubled the original volume of water in the bag.
  5. Pour out half of the water in the bag into a container and discard it.
  6. Repeat step 5, adding a half cup of aquarium water ever 5 minutes until you have doubled the original volume of water in the bag.
  7. Do not add the bag water to your tank.  Scoop or net the fish out of the bag and place it into the aquarium.
  8. Observe the new arrival from a distance.  New fish may hide for several days. Searching through the aquarium with your hands will only add more stress.

Coral and Invertebrate Acclimation

The following method is preferred for more sensitive species like shrimp, snails, corals, and delicate fish.  Hardier species of coral can be introduced using the float method described above.

  1. Place a 5 gallon aquarium bucket next to the tank.
  2. Open the bag and gently pour the water including the animal into the bucket. You may need to prop up one side of the bucket if there is not enough water to keep the animal(s) submerged.  Fish and invertebrates will need separate buckets.
  3. Using a length of airline tubing and an air control valve, start a siphon from your aquarium down to the bucket.  Adjust the valve to obtain a drip rate of 2-4 drops per second.
  4. Once the water volume in the bucket has doubled, remove half of the water.  Continue dripping until water volume has again doubled.
  5. Transfer the animal(s) to the aquarium.


  • A coral dip product is highly recommended immediately before introducing a new coral to the aquarium.  Follow the instructions carefully.
  • Do not excessively handle new corals.  Place them in a spot where they will not fall over or be disturbed for a week or two.
  • Never expose sponges to air.

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