Please help! My Zoa's are disappearing!

[jdeb101]

About half of my zoa's have either melted away or something is eating them. I noticed first sign of this maybe a month or so ago with one colony and didn't think much of it. Everything was looking fine for a while but looking at my tank last night I noticed also a huge orange zoa colony is almost completely wiped out, along with some of my rastas, and a plug that was completely covered with green zoas now just has a couple along the edge.

Being halloween and all last night I didn't have much time to do anything such as tests. I did however test maybe 3 weeks ago and everything checked out normal (alk was a little low but it's always been low in my tank).

I have made some additions / changes to my tank a little over a month ago and suspect one of these is the culprit.

1. Added biowheel hob filter and started running carbon. I haven't changed the blue carbon filters yet, maybe its leaching something? Is it making the water too clean?? I read zoa's prefer dirty water..

2. Added to my CUC. Added about 6 hermits, 1 emerald crab, and a skunk shrimp. I havent witnessed any of them picking at corals, but my guess is they do it at night if they are doing it...

3. My last water change was done with a new box of salt mix. Perhaps something is off in the new batch? Using Reef Crystals (same brand I've always used). Should I test the fresh batch? If yes, what should I test for?

4. Replaced my bulbs. I have a 6 bulb T5 Reef Elite fixture. I would replace two of the bulbs at a time over a month period. Note that I replaced with same types of bulbs, no new color spectrum or anything..

TIA to anyone that can offer advice!

 

[jokersplayground]

i would look for zoa eating nudis. it sounds like that is your problem.

 

[jdeb101]

I didn't see any signs of pests. I even peaked with a flashlight for 10 minutes last night.

 

[jokersplayground]

that would be my guess or it can be something in your water.

 

[wrassefan]

I would test ammonia, alk, mag, calcium and salinity...any temperature swings?

 

[jdeb101]

Hopefully I can test tonight. no temp swings.

 

[wrassefan]

I normally test the new salt mix each water change....you can get a huge swing in parameters if you are off and the new water brings everything back in line

 

[jdeb101]

I assume I only need to test the fresh batch for alk, mag, calcium and salinity?

 

[Matt W]

I have heard the zoa nudis can be very hard to find.

 

[JohnK]

I have heard the zoa nudis can be very hard to find.

Yes, they blend in very wll and can be extremely hard to spot. IME they are a lot like red acro bugs in the sense that they are almost impossible to spot, but once you have seen them in person they become a lot easier to see.

Also, do you know what sundail snails look like? That could be another culprit.

 

[jdeb101]

I found some pics on http://melevsreef.com/id/snails.html . I didn't notice any of either, but will take another closer look tonight. Maybe I should take a frag out and dip it to see if any pest dies off??

I have a gut feeling that my emerald or a hermit may be eating them. Is that possible? Has anyone witnessed such thing?

 

[Dekon]

There are some posts on here and other sites about zoas disappearing. I had this happen to me with some Tubs Blue zoas. I had a frag of 10 polyps to start, over the course of a few months it turned into 50+. Then, they slowly disappeared over the course of a month. None of my other zoas were effected; just the Tubs blue and there was a colony of Armor of God right next to the TB's.

 

[Pat02026]

The nudis blend in well, so well in fact they camouflage themselves since they turn whatever color the zoas they are eating. If you stare at a colony that is disappearing you will see it if that's your problem. The pigment is virtually identical to whatever they're working on so with just a quick glance you won't see them. Search on them here, there's a lot of good info and I personally dealt with them early this year; flatworm exit worked for me.

 

[jdeb101]

Dekon... did you ever find out the cause?

Pat02026... I'll give them a good look tonight. Funny you mention FW Exit, because I've been meaning to dose that for some time now. I've had flatworms in my tank for quite some time now.

 

[jdeb101]

So just spent about two hours with my tank. Tests for ammonia salinity and nitrates all showed fine. My all was really low, maybe 1-1 1/2 meq/L. My new sw batch came out to 2meq/L and I did a 25% water change. I looks Dover all my zoa colonies and didn't find any pests. I also removed the carbon I was running.

I'm stumped...

 

[GobyWanKenobie]

I have problems with zoas too. It always seems like my favorite ones just melt away. I've tried dips, etc., but once they stopped opening, it was a lost cause. Somehow the boring ones seem to survive and multiply, so it's not like all my zoas disappear. I've never been able to figure out what the problem is. Wish I could help, but my luck isn't any better.

 

[jdeb101]

Ya I just don't get it... Two types of zoas that melted were in my tank for years. I'll see what happens the next few days and may try giving some a dip just to be sure of no pests.

 

[dz6t]

What type of carbon are you using? Hopefully not Kent.

 

[jdeb101]

It was marine land.

 

[jdeb101]

So I took another peak in the tank this morning and saw a few of these on the glass. Look like baby turbo's to me. Safe??