reef tank

Compatibility between corals, how do you know?

How to check if corals are compatible in an aquarium?

Today we are talking about compatibility between corals, or how to check if they will be able to live together peacefully.

The main cause of incompatibility between corals is territorial, sometimes leading to a fearsome chemical war between neighbours. Corals can even atomize an entire aquarium if they take up too much space in relation to the volume of the aquarium. Finally, some corals become so large that they cast a devastating shadow on the corals below.


Here are some tests you can perform to check the compatibility between 2 corals:

Place two coral fragments side by side that you wish to experiment with in a side tank with only an air pump, minimal lighting and heating. Wait a week or two, if the corals do not attack, it is almost guaranteed that they will live in peace.
If you wish to experiment with two “toxin-screening” corals, do so in a “quarantine” aquarium with proper lighting. This quarantine will serve to protect the other inhabitants of your aquarium.

When buying corals, you should consider their growth potential. Place them in places where the shadows created by their growth will not disturb their neighbours.

Then, some corals can move around (such as anemones for example or even flat corals, such as Fungia spp). They can make their way to areas of the aquarium that are more suitable for them. If you have these types of wandering corals, make sure they have a path that will not put them in contact with other aquarium inhabitants.

Most Sarcophyton spp. type leather corals are placed on the bottom so that they can grow in peace. It is also useful to prune them, preferably outside the aquarium as they can excrete toxins. If you cannot do this outside the aquarium, provide a good bag of activated charcoal when pruning to avoid any excess toxin being released.

With these preventive actions to ensure compatibility between corals, you can have an aquarium as full as you want. Luckily, not all corals die from stings and most can grow back after an express rescue.