Being able to have a mini version of tropical coral reefs in your home is an amazing and rewarding experience. It takes work and dedication. But if done properly, you can have a beautiful, healthy little reef right in your own home. And what is the most important part of that reef? The corals, of course! In this article we will give you a step-by-step guide to acclimating your corals in a new reef tank.

Choosing Your Coral

It’s important to make an informed decision on which type of coral to choose. Generally, you can break corals down to either soft corals or hard corals. Soft coral doesn’t have an internal skeleton, allowing it to bend and dance in the water. Soft coral is easier to care for because it is more tolerant to changes in water chemistry and it grows quickly. It also feeds on water-borne particles, meaning your tank doesn’t have to be spotless. Generally it prefers moderate light conditions too. Be sure to research each species as some can be predatory towards other corals. Common soft coral species include Zoanthids or Mushrooms.  

Hard corals are split into two groups again, Large Polyp Stonies (LPS Corals) or Small Polyp Stony Corals (SPS Corals). LPS Corals are recognizable by their large head, whereas the LPS Corals have flowery spots. Both groups have a hard, stony skeleton and are more difficult to care for. This is due to the fact that they require high light levels and LPS Corals are more aggressive and can sting. Common LPS Corals include Brain Coral and Candy Cane Coral. Common SPS Corals include Acropora and Montipora.

Acclimating Your Corals

The proper acclimation of a new arrival is extremely important given the amount of stress the coral has experienced before arriving at your door. We recommend that, immediately upon receipt of the livestock, the following protocol be followed. When acclimating, you are gradually allowing the coral to adjust to the new water parameters. The three which create the biggest problems are pH, salinity and temperature. The process is very quick and should take less than half an hour to complete.

Turn aquarium lights off

For the last day or so the livestock has been in total darkness, and will not respond instantly to high-output aquarium lighting. You eliminate a potential source of stress for the new arrival by turning the lights off. In general, overexposure to light can be a concern with new additions to your reef tank. 

Empty the container into a slightly larger tub

Whether you are adding hard stony corals whether they are Large Polyp Stonies (LPS Corals) or Small Polyp Stony Corals (SPS Corals) or Soft Corals such as Zoanthids or Mushrooms, it is highly recommended to acclimate the corals from the bag of water they arrived in. To acclimate the new corals you can use a small plastic tub. The aim of this is to provide ample volume to add water from the aquarium tank to the tub with your new additions.

NOTE: NEVER ALLOW THE BAG OF WATER TO ENTER YOUR TANK. Coral can excrete toxic chemicals and cause death and destruction to your system!

Add ½ cup of tank water every 20 minutes

The slower you add the water the better. Corals and other invertebrates are sensitive to fluctuations in pH and especially salinity. Also consider how you can regulate water temperature here. You may be able to float the tub at the top of your aquarium tank to prevent temperature drop-offs.

After adding water to your container 5 times over 1hr to 1.5hrs, gently remove coral from the container and place the corals into your tank

Discard water and place coral into the recommended zone. The coral is recommended to reside in an area of med-high light, dim lights or run actinic lighting only during this initial introduction period. During the course of the next 2-3 days, many advanced aquarists reduce the hours/intensity of the system. This allows the coral to gradually grow accustomed to the lighting. Remember if the coral is photosynthetic it must have lighting. If lighting is not provided, the coral’s energy needs will not be met. This will cause the coral to “employ” additional staff members of internal algae (zooxanthellae), increasing the brown pigmentation of the coral, hence the change in color you may have seen in corals not properly housed.

Final Notes

When they arrive at your door, your new corals might appear extremely stressed. One of the most stressful things for coral is shipping them out to their new home. Corals may take a few days until they recover some semblance of their previous appearance. So be patient, careful and cautious with your new additions.