What could be the cause of a reef aquarium with soft corals shrinking and diminishing while the hard corals are thriving at the same time???

Today’s blog post is inspired by a question from Lori who emailed me via www.SaltwaterAquariumAdvice.com, who is having this very problem.

Beautiful carnation coral

Beautiful carnation coral

She asks me “ my soft corals are diminishing while my hard corals are flourishing. Water parameters seem to test within normal limits. Since I do not want to loose my neon green hairy mushroom that has lost half its size, what can I change to help the softies in this reef tank?

Generally speaking soft corals are usually very robust, tolerant and hardy in reef tanks and the problem would more commonly with the stony corals in a situation like this. What could be some common reasons?

Too much light?

Soft corals as a general rule require less intense  lighting than more-fussy stony corals. It could be that the softies have simply had too much and are getting photo-saturated if not gradually exposed to intense lighting set ups. This would be extremely likely if the lighting set-up was new. If this is the case simply move them down the tank 🙂

Disease or infection?

Its pretty easy to check for any lesions or discolouring on soft corals and rule this out as a cause. Naturally they have very few predators and parasites in the wild (which is why you never see soft coral fouled up with algae, barnacles or the like) but do check for any commensal crabs that could be attacking them and get rid of them if they are present.

Chemical warfare?

mushroom coralUsually soft corals are not on the receiving end of this as they are quite capable of aggressively attacking their neighbours (especially mushrooms) and ending up on top. LPS corals can give soft corals a good run for their money if going head to head.  Ensure there is at least 6 inches of space separating the softies from anything and if in doubt add some activated carbon to the water to help mop up any toxins.

Playing dead?

Before getting too worked up about this problem remember that often these animals can and do shrink and get flaccid and wrinkled for no apparent cause, then days later spring back to life. Give it some time and see what happens as this is commonly part of the life cycle for captive soft corals.

Your water quality is fine which is a great sign (as is the hard corals doing well). Watch for  any slime/ mucus or any other tissue being shed as this will be toxic to your water and usually accompanies a return to health of your soft corals. Do check your mechanical components too to ensure they are working well and are not the cause of the problem.

I would hazard a guess that this is what you corals are going through, keep an eye on them and let me know what happens. You can add some iodine and increase random water movement around them to help them out.