RSS Breaking Up is Hard to do

MASA Admin

8 May 2007
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There’s a dirty little secret that no one in the hobby will tell you, but I will. Once you get good at this, corals grow, and no I don’t mean the “1cm per year” that your dive boat captain will recite when he tells you not to touch the corals. No I mean they really grow, so much so that if you give them enough time and treat them well they will literally grow right out of the tank.

Now for those of you that frag everything once there is a ½” or more of growth this is great. But for those of us that enjoy growing nice full colonies this can be a problem. Actually it can be a multitude of problems. How do you decide where and when to separate a colony that is overgrowing its neighbors? What do you do with the large piece you’ve removed? How do you reduce the stress on a tank that cutting a big colony can produce in a small closed system?

if not kept in check corals like the staghorn in the background can overgrow a tank and can grow so much it bleaches on the bottom

Now that you’ve got a great looking tank with everything happy and in the right spot how can you slow the growth so you don’t have to regularly have to cut out a large portion of the tank? These are just some of the problems we generally don’t think about when we set up our tanks and if you are like me, overstock them. And lastly why the heck did I ever put a Montipora in my tank?

I know this sounds like a nice problem to have, but after having everything from a 20 gallon nano to a 1200 gallon sps tank, I have come to realize that breaking off or cutting big chunks or colonies of corals is one of my least favorite activities that I have to do in my tanks. However it is a necessary evil when things really start growing, which is what everyone wants.

A section of Sanjay’s tank approximately 16 months ago

The same section of Sanjay’s tank a year later

From my experience corals are either growing and thriving, or they are failing and dying, there really is no in between. And considering what we have invested in being successful I will take growing and thriving every time.For those of you that garden and have shade beds or some other kind of perennial plants the problem is similar, you have to regularly thin the bed or else either one plant will dominate or the plant will die out from the center. However unlike plants, corals tend to encrust on the substrate on which they are growing.

As a result, thinning them or cutting them takes a little more effort, but with the right tools it can be done with minimal stress on either you or the tank. As with everything in this hobby having the right tools makes doing the job much easier. My 300 gallon tank recently reached 3 years of age and I have found that it is usually at this point that I have had to do some major pruning of the corals. In this case I realized that the entire right hand side of the tank was pretty much dominated by three corals.

Due to a fast growing Acropora nasuta overgrowing the other corals it had to be chiseld out

A Montipora spumosa had encrusted on most of the live rock and was starting to overgrow everything, including the neighboring Acropora colonies and frags that were growing vertically would not be spared its wrath. A Montipora aequituberculata that had grown from a frag only a year earlier to the point where it was now growing over the top of everything in its path and a colony of Seriatopora “bird of paradise” that was dominating to the point that it had filled up the side of the tank and was encrusting on the glass.

As with your children you don’t really realize how much they have grown until you are either away from them for a while or until you look at the big picture. In this instance I did not realize how much these corals were overgrowing their neighbors until I looked at the tank from the top down. Then it was readily apparent that these corals needed to be dramatically thinned down.

At first I tried the old ‘just break them off’ method of thinning, but this was a disaster as all it did was produce a mess of small broken frags and tons of slime which stressed out the entire tank. So knowing that, continuing this method was a bad idea so I went to what I thought would be a somewhat rougher means of thinning them in that I brought out the hammer, chisels and screwdrivers. I had used these in the past in my 1200-gallon tank but had not had to use them in a while.

Required tools for cutting and pruning large coral colonies

Since this was a smaller tank I got a couple of smaller chisels as well as a couple of screwdrivers that I could also use for finer work. Fortunately corals are not as dense as rocks, so you do not have to use much force to have the chisel or screwdriver break through the coral and the live rock. For this reason you also do not need a large hammer in order to get the desired effect. Since you are only really tapping lightly under water, the small hammer also does not cause the splashing that a larger hammer would.

For breaking up the colonies you simply need to use the small chisels or screwdrivers to kind of score the colony where you want to break it off. I make punctures in the encrusted portion of the colonies or sections I want to remove at approximately ½”-3/4” intervals along the colony and once these are completed I can usually lift the piece I want to remove away from the remaining colony. If it will not break then the larger chisel can be used to connect the punctures. The small chisels can also be used to pry the colony off of the live rock it is sitting on or is attached to.

Small Montiporas like thesse Leng Sy caps can quickly dominate a tank unless they are kept in check with cutting and trimming

However even when being careful not to overly stress the coral I am cutting they still tend to produce a lot of slime which stresses not only them, but also the neighboring corals. So to minimize the effects of this I have learned to do this work right before the weekly water change. When removing water from the tank for the change I remove the slime and debris that cutting has caused to minimize stress in the tank.

I also add an extra bag or two of carbon to further reduce the stress from this as well. Since most of the time the fragmented piece is not going to remain in the tank it is removed to a bucket containing tank water and carbon as soon as it broken away. Lastly if it looks like the corals are stressed in any way from this procedure extra powerheads are added to the tank to increase the flow and to keep the slime from settling and stressing any of the nearby corals.

With proper planning and spacing corals can grow to a stunning display as shown in Sanjay’s tank

Before doing this kind of drastic pruning I strongly recommend that you not only plan what you need to break off, but also where you are going to put the broken pieces. If you are putting it in back in the same tank that is no problem or if you are placing it another of your tanks like a frag tank, that is also good. But before you start cutting you need to have a home for the piece you have removed. Often times I have not realized how big the chunk of coral I was removing was going to be and as a result I had not prepared space for it and so I was left scrambling to find it a home.

As a result I have learned to talk with the shops near me as well as some of fellow nearby hobbyists to make sure that when I was taking pieces out of my tank I had a new home for them prepared. Nothing is worse than removing a chunk of coral that you like and sticking it in a bucket thinking you will find it a quick home only to watch it die in the bucket after it has had to sit there for a couple of days.

The author’s old 1200 gallon tank that required monitoring and cutting corals to keep one coral from dominating

So as with everything in this hobby be prepared. The level of success we have achieved today at keeping sps and other corals is unprecedented. We need to be better at allowing for the rapid growth that many of us now achieve with these corals. And while this may sound strange, for some of us there is a need to find ways to slow the growth of our corals, while still keeping them healthy, otherwise we need to do regular massive pruning in our tanks.

This is not healthy for our tanks, or our corals and is also stressful for us. I wish I could say I was there and had figured it out, but as I said earlier my corals either grow like crazy and thrive or show no growth and perish. I’m sure there is some happy medium and I would enjoy hearing from anyone who has achieved this.

I ask this as I especially love Montiporas and as everyone knows who keeps them they for the most part grow like weeds and cover everything in their path. Except of course for the rare ones that Jason Fox is bringing in, which are the exception as the slow-growing Montiporas I seek. So maybe the answer is to only keep slow-growing sps, but that to me seems too limiting.
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