Zoas shrinking and dieing

[cmsargent]

I’m hoping someone can give me some advice on what is going on with my zoas.

I bought a rock that had 5 colonies of 3 different types of zoas. Each colony has 10-20 polyps with small amounts of bare rock between the colonies. When I bought the rock a handful of polyps in two colonies on one side weren’t open. I though it was just due to shipping stress so I didn’t worry about it. I did a short FW and lugal’s dip and added them to my tank. It’s a new tank set up about 2 months at that point and these were the 1st zoas in the tank (I’ve since added one other frag). After about a week the polyps still had not opened and some were obviously dead (starting to rot). So I removed the rock, cut away all the dead tissue as well as some of the surrounding live tissue, and did another FW/Lugal’s dip (this time for 30 mins. with a stronger solution). All the remaining polyps looked fine for about a week and then the polyps from the 2 affected colonies begin to wither, closed and died. The remaining 3 colonies appeared to be fine again for about a week. Then I noticed the polyps of the colony in the middle of the rock were getting smaller. Over the last two weeks they’ve gotten progressively smaller but are still opening. They are tiny now…about the size of a pin head but all except a few are still opening. I don't have a pic but can post one later tonight if it'll help

Any ideas as to what might be causing this? The other zoa frag and the 2 colonies on the far side of the rock are fine and even adding new polyps. I haven’t seen any signs of anything eating the polyps (and wouldn’t the FW dips taken care of any predators). I’ve read the thread about the dreaded zoa pox but I haven’t seen any obvious white spots (although it is a bit hard to tell as these have light colored skin). It seems like this must be something infectious as it’s spreading across the zoa rock. I don’t think it would be a problem with water quality as the other zoas (and mushrooms, macroalgae, peppermint shrimp, hermits, snails, and feather dusters) are fine (pH 8.2, Sal. 1.024, temp 78). My ammonia and nitrites have consistently been 0 for a couple of months now. Nitrates are a little high 15-20 and I’m working on lowering them. Weekly water changes of around 10%. I haven’t been adding or dosing anything as this tank is still new and doesn’t have much in it. Water changes have been keeping alk and cal within a decent range (around 350 ppm). Lighting should also be ok (PC dual daylight/actinic around 4wpg).

I think this may be the mysterious wasting disease discussed in the sticky threads. At this point I’m mostly concerned with how to salvage the situation in regard to QT and fallowing my tank. I’m thinking I should remove this rock and the other frag from my tank and let it go for awhile with no zoa in it as all. Hopefully this would rid the tank of whatever the infectious agent causing this is. Any ideas of how long to wait before adding zoas again?

I’m also thinking about breaking up this rock so I can isolate the 2 unaffected colonies. How long would you recommend QT these colonies before I can assume they are disease free? If I break up the rock but QT all the colonies in the same tank will it still spread even if they’re not near eachother? Should I toss the affected colony in hopes of saving the others? Also what is the lowest lighting that zoa frags can survive in over the long term? My QT tank just has standard fluorescent lights so I’m worried how these frags will do in the lower light conditions. Do I need to buy another light?

Sorry for the long message and all the questions
Thanks, Chris

Oh and by the way can you ID and tell me what they’re worth? JKing

 

[MUCHO REEF]

Hello cmsargent, sorry about your bad luck.

You stated, "When I bought the rock a handful of polyps in two colonies on one side weren’t open. I though it was just due to shipping stress so I didn’t worry about it".

I have learned from experience to treat new zoa purchases the same as new fish purchases. If a fish isn't really swimming the way it should, and it's by nature an active fish, I won't buy it. If I really want it and it just came in, I will offer the LFS a deposit to hold it for 24 to 48 for observation, most stores will do this. I treat new zoa purchases the same way. If they aren't open and have been at the LFS for days or weeks and they haven't opened yet, that's a sure sign that there is an issue with them. If they are new arrivals, it could just be stressed or they are acclimating and it will take a day or two. In that case, a deposit should be offered to hold them. It's very possible you had a rock that was already showing signs of the beginning stages of BI, fungus, wasting, die off etc, but the physical signs weren't manifested until you took them home and placed them in your tank. New arrivals are very vulnerable when placed in a new tank. At this point I would try to cut your loses and frag up anything that is in serious decline.

"did another FW/Lugal’s dip (this time for 30 mins. with a stronger solution). "

Just curious why you did a full 30 minute dip?

I would also consider gradually raising your temp to 80 degrees if you can.

Have you ever considered adding vitamins and amino acids?

"I think this may be the mysterious wasting disease discussed in the sticky threads"

I wouldn't necessarily say it's a mystery disease, since they were already showing signs of retraction when you purchased them. Whatever it was, it gradually affected the rest of the colony.

I would QT those colonies that are affected for a couple of weeks. I wouldn't take every colony out unless you see signs of them being affected also.

If you smell the rock and it has a foul, decaying smell, yes, you should frag 3 or 4 rows away from the affected area, then trash the rock with the decaying zoas. Be sure to use reef safe gloves and using a soft tooth brush, really clean up the edges and dip them in a small bowl with a few drops of Lugols for a swooshing 30 seconds. The medicinal properties of the iodine will also aid in the recovery. Then dip in a bowl of tank water outside of your tank, then place the frags/colonies in your QT and leave the colony in one spot. Be sure that current wiggles the polyps here. It will also help rid the colony of any chards left from the surgery process. Hope I didn't miss something.

"Also what is the lowest lighting that zoa frags can survive in over the long term? "

Zoas can and will adapt to most types of lighting. Standard 40 watt lighting is the exception. Will they live, yes, will they be as vibrant in color, NO. Some will even fade and in time they won't look as healthy. But true enough, they can and will live. If you can buy or borrow a small PC fixture for a few weeks, I would recommend that. Zoas derive there sustainable nutrition from light, it's not good to reduce said lighting when you are trying to save them and the light, as well as stable tank parameters will greatly help them to recover.

Hang tough,

Mucho