Today, we are going to go over setting up a quarantine tank for corals, instead of fish, and show you why it is a smart idea to have a separate tank dedicated to the isolation and observation of corals. New corals can carry a wide variety of not-so-pleasant hitchhikers into your tank. It is even possible for a coral frag or small colony to carry diseases and parasites, such as Ich, that can not only affect other corals, but also fish and other animals in your tank. 

Do I Really Need A Separate Coral Quarantine Tank?

Some of you are probably thinking "I dip all my corals prior to going into my tank, so why would I isolate them, too?" The answer is simple: coral dips are not 100% effective. Even if you dip your corals twice, you will never completely eliminate the risks.

That being said, dipping your corals does drastically reduce your chances of introducing a harmful pathogen or parasite, and exactly why we always recommend you dip your corals. Even if you're using a coral isolation tank, we suggest dipping corals whenever they are being transferred into a new aquarium, even when going from your isolation tank into your display. We carry several great coral dips including the Coral Rx, Two Little Fishies Coral Revive, and Tropic Marin Pro Coral Cure

Even with a solid coral dip routine, some pests can be extremely difficult to get rid of. Should you be lucky enough to kill all of the visible pests on your coral, there is a high likelihood their eggs will survive. Most eggs of coral pests cannot be eradicated with coral dips and can hatch weeks after being introduced into your aquarium. Additionally, some pests may be hidden so deep within the frag plug or rock that a relatively short dip may not deliver a strong enough dosage to reach them.

Isolating and observing your corals in a separate coral quarantine tank is a great way to further protect your reef tank from dangerous coral pests and pathogens.

During isolation, corals also get the chance to acclimate to aquarium conditions and water chemistry, new frags will have time to heal, you can spot feed corals without competition for food, and you get the chance to observe the health of the corals more closely before gluing onto your rocks. Same benefits as a frag rack, except further reducing the risks of introducing pests!   

Coral Dip
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Tank Setup

A coral QT does not have to be complicated, here is a basic list of all the main components you will need. 

  • 5-20 gallon tank
  • small power filter
  • heater
  • lighting
  • small powerhead
  • frag rack
  • clean saltwater

A small tank of about 10-20 gallons is all you need for isolating corals.  Having a shallow tank makes it easy to provide ample lighting and flow and will also make it much easier to closely observe the new corals. Once you have a tank, you will need a filter to keep the water clean and oxygenated. Unlike a fish tank, a coral quarantine tank will experience little to no waste so keeping nitrates down should be easy with a small hang-on power filter or canister filter. 

With a small, shallow tank it is easy to find affordable lighting. LED strip lights or medium output panel-style LED such as the Current USA Orbit or AquaMaxx Prism will work just fine. 

For water flow, you want a small powerhead such as the Sicce Voyager Nano or a small Maxi-Jet will work out great for tanks around 10 gallons. You do not need anything fancy, just enough to circulate the water inside the tank and keep the corals happy.

A quality heater, such as the Eheim Jager, works well for keeping the temperature stable.

DIY egg crate or frag racks are great for holding the corals inside the tank. You can easily move them around in the aquarium to accommodate the light and flow requirements of the specific coral.

Once you got everything together, bacteria supplements will most definitely help the process along. You can add some cycled bio-media or a piece of live rock but this is not required. Corals are not really sensitive to ammonia or nitrite like fish are.  Ultimately, just do some regular water exchanges to keep water chemistry (calcium/alkalinity/pH) stable and this should suffice for nutrient export. The water will be ready for corals immediately meaning you can set everything up and add coral on the same day.  

Coral Dip Diagram

Coral QT Process

Once corals have been dipped, rinse in a bath of salt water to get rid of leftover dip, and add them to the quarantine tank.

Check them regularly for healthy polyp extension and look closely at the coral tissue. The base of the coral is the most common area to see tissue recession and pests, keep a very close eye on this area. Pests have some pretty stealthy camouflage so take the time to stare at the corals daily. It will take some practice to properly ID all of the various coral pests. This, perhaps, is one the most difficult parts, spotting and identifying the pests.

Sometimes signs of stress and infection may not be immediately visible so be sure to give the coral plenty of time for observation. We generally recommend isolation for 30-60 days without any signs of infection or diseases. Ideal the coral begins to expand and grow while in isolation. 

Physical removal is one of the best ways to completely eradicate many coral predators. Being in isolation makes it much easier to see these little organisms and get them out of the tank using forceps or similar tools. Remember to agitate the coral dip, shaking the coral while it's in the solution helps dislodge dying pests. You can also safely dip an infected coral multiple times and place it back into quarantine to help eradicate various problems. Just give those corals time to recover in between dips. 

Unlike a fish quarantine tank, it is not typical for you to directly medicate the entire coral quarantine tank. It is best to treat corals in a separate container, rinse them in clean saltwater, and then place them back into quarantine for observation.

Don’t forget to have fragging supplies, a specimen cup, and appropriate test kits handy. You do want to monitor temperature, pH, and salinity which means water changes and freshwater top off will be a part of the process.  While you won't see a ton of major element consumption with a handful of frags, pH and salinity swings can be just as deadly.