Palau Nepthea Question

[Rjohn]

I was buying a couple of frags the other day from a reefer and he was telling m e that he wouldn't have palau nephthea in his tank cause it puts out so much garbage. He said that a large piece could "poison" a tank. I have a small piece that seems to be doing well and some zoas and palys near it seem to be declining. Has anyone had any experience with this?

Just as an experiment, I am going to move the palau to the other end of my tank. Maybe it will put some decline into my forest of kenya trees.

[caferacermike]

All leathers produce and exude a toxic slime that can kill off surrounding corals. As you must know by now, corals extend some sort of territory defense mechanism. The stronger coral wins. Leathers will shed a slime that will flow over to near by inhabitants stunting them or killing them back. This then allows the leather to continue to grow. If the neighbor coral has a stronger bite, it can kill the leather. In a contained environment such as an aquarium, the toxins can affect everything within the tank, not just nearby corals. This would be because every coral is a nearby coral in a contained environment. Most SPS dedicated reefers will not allow any type of leather within their tank. The defense mechanism is to far reaching and indiscriminate. Most SPS and LPS have some sort of territory defense mechanism that includes polyps or sweeper tentacles that reach over and gight encroaching corals, again the stronger coral wins. However you rarely lose an entire piece do to this. One coral recedes back a little while the other coral grows a little. If a large leather exudes a large slime cloud, it can envelope an entire coral colony killing it all. If you choose to run a mixed reef that includes SPS and leathers, you should be running a very efficient (large for the tank volume) skimmer, possibly a reactor full of carbon that is changed out frequently, and frequent water changes of a substantial amount. This will help prevent the buildup of these toxins over time. Also large amounts of flow will help to break up and spread out the toxins, thus weakening its concentration and potency. Large toadstools are especially noted for this. If you keep one under low flow conditions they can suffocate themselves. They rely on high flow to help them shed this slime. It is thought that the slime covers them during the day helping them to attract food, at night they shed this coating helping to sting away coral competitors. If there is not enough flow around your toadstool the polyps will not extend. Over time the slime slowly suffocates the coral. If you see this on your leathers, them not extending their polyps, sometimes you can rub them clean with a soft toothbrush and within a day they will begin to recover and look better.

So then there is no right or wrong answer when it comes to whether you should keep them. It's like most of the reef hobby, subjective. If you want a high density SPS/acro tank, then I wouldn't risk it. However some risk it and have no troubles with it.

[mhart032]

Rjohn from what i understand about the palau is that its very toxic to surrounding corals, although i would like to have some "being that its said that there is none in the seas anymore" but i dont think it would be a good fit im my little 34g Solana, from what i have read about it in other forums it does pretty well all by itself on a rock island type thing. Also the use of carbon mite help with the chemical warfare?

[Derek]

I have a few leathers in my tank. I just run carbon and give them some room.

[Rjohn]

Silly me. I didn't think of the palau as a leather. I have one ot two other leathers but they have lots of room around them. I have rearranged a bit and I will see what comes of it.

[Timfish]

The term for this is allelopathy and it's really quite widespread. Here's a link for anybody interested in a definition.

http://en.wikipedia....iki/Allelopathy

While allelopathy is I'm sure a partial explanation for some of the problems we encounter in our tanks as the above posts point out it shouldn't be to much of an issue if good maintenance procedures are followed. Most of my tanks are mixed leather and stoney corals with mushrooms and polyps and have been for years. I know of a tank that for years had two (or more, several were harvested that I know of) Sarcophyton leathers that took up a third of the tank which also housed healthy growths of acropora, plating montipora and frogspawn, however when the owner expierenced some health problems and the system was not maintaned the acro's and monti's died off.

I want to expound on Caferacermike's comments about taking risks. We are potentially dealing with thousands of species many of which are not found together in the wild and most of which are very poorly researched as well. I'm inclined to believe there are combinations we are maintaining that in the future research may show should not be housed in the same system. While anecdotal in many cases (like my example above) forums like this are an invaluable source for information to help the aquarist decide whether or not to "take the risk".