How far apart should I place my corals?

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Jeremy Gay advises on how to safely place corals in a tank.

Q: Is there a guideline as to how far apart corals should be positioned in a tank? I only have a selection of soft corals like button polyps, Green star polyps and some mushroom corals but I don’t want them to sting each other. 

REECE, VIA EMAIL

A: Jeremy says: There isn’t a fixed guide on how far apart you should place corals as every species has a different reach when it comes to fighting and stinging other corals. Some of the worst are LPS corals such as Galaxea, Bubble corals and Chalice corals, which may reach 15cm or more with their wispy, yet highly damaging, sweeper tentacles. You actually have three of the least aggressive corals there in mushrooms, GSP and zoas, but what they lack in stinging power they make up for in invasiveness, simply overgrowing other coral species. If the zoas, mushrooms and star polyps aren’t physically touching each other then they won’t sting one another either, so could literally be placed 2-3cm apart. But at the same time their colonies may spread by as much as 2cm in a month, so I’d advise placing them at least a hand’s width apart, if you can, to allow for growth.