Zoas in Trouble, Please Make Suggestions (1 Viewer)

Howdy!

I think I have several issues going on with my tank including a water chemistry issue, but I'll cover the chemistry issue in a separate thread. But something is killing my zoas.

Here is a pic from 2 months ago of 3 of the 4 zoa colonies on this one rock. It was the only pic I could find of any of the colonies on this rock.


Here's a pic of the 4 colonies taken today. Sad. And what is the green stuff all over this rock? I know it's algae but what kind? It's not like this in the rest of my tank. And I apologize for the lighting differences.


Here is a close up from a week ago.


Here is a pic taken this morning. Look at the 2 starfish. Are they eating my polyps or just the green stuff?? It's hard to tell. But it looks like where the starfish has been there are no longer any polyps. I've had these starfish a long time. Long before I started adding corals again. Never seen them eat zoas before. Seems like this green stuff is killing the zoas and the starfish swoop in and eat whatever the green stuff is attached too.


I would say 90% of my Zoas are now suffering and showing signs of stress. Not to the extent of these 4 colonies, but they only half open and don't extend their tentacles very much. Most of my other corals are not showing signs of stress especially my LPS and anemones. Several of my SPS however no longer extend their polyps as well as my green toadstool and kenya trees when the lights come on. This green stuff did not start popping up until several weeks after I started dosing nitrates. My nitrates had dropped to under 2 ppm a month and a half ago so I started dosing potassium nitrate to bring levels up to 10 ppm. These 4 colonies started showing stress several weeks after I started dosing so I allowed the nitrates to drop back down to 5 ppm and that's mostly where I try to keep the nitrates now. So what is this green stuff? Is it blue green cyano? Or something else? What should I do at this point?? I know they can be replaced, but I REALLY hate seeing my favorite corals (zoas)...die. Sucks. Please make some suggestions. I'm really struggling with this.

I would wager you have zoa eating nudibranches. Do you have one of those UV flashlights? If you do, use it at night and you will see them on your zoas. They will glow like a firefly. If you don't have one of those lights, swing by and borrow mine, or you can get them online for about 20 bucks. If you find that is what you have, sucking them out with a turkey baster every night will eventually get them. They lay eggs so you have to keep at it until all the eggs have hatched. They don't mature enough to lay eggs for a few weeks so persistence will get them.

Have you double and triple checked your salinity? I have noticed zoas suffering from this in the past.


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I won't rule out a water quality issue either. The green stuff is blue/green cyano so you may have some water quality issues there as well. The best solution for that is lots of water changes. Make sure your TDS is zero on your RODI water.

You can try this and it will definitely rule out at lest the pest issues. Zoas are very hardy so you can treat them with strong chemicals with out issue. Sometime one or two of my colonies will close up so this is what I do. I setup a revive dip and two rinses get a very soft bristle tooth brush I take them out and put them directly in the dip (I always use tank water for dips and rinses) let them soak for about 10 minutes then give them a light brushing. Don’t poke at them just a light brushing side to side. Then rinse twice and put them back in. The polyps usually open within a couple hours. If that doesn’t get them to open I would put my money on water quality. You could go further and do the Bayer dip (I’ve never tried this)


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My thought would be zoa eating nudibranch or Astrenia Starfish! I had the same issue not too long ago. I started looking at my tank a few hrs after lights out with a red flashlight and spotted several or these nuisance starfish cupped over the top of my zoas like little mushroom caps Took about a week of manually removing them, but things bounced back quickly.

sneezebeetle said:

My thought would be zoa eating nudibranch or Astrenia Starfish! I had the same issue not too long ago. I started looking at my tank a few hrs after lights out with a red flashlight and spotted several or these nuisance starfish cupped over the top of my zoas like little mushroom caps Took about a week of manually removing them, but things bounced back quickly.

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Good point. I forgot about those starfish sometimes eating zoas. I had them devour an entire pipe organ colony one time. Did the same thing. Cupped themselves over the entire polyp. I would remove them at night with tweezers.

webster1234 said:

Good point. I forgot about those starfish sometimes eating zoas. I had them devour an entire pipe organ colony one time. Did the same thing. Cupped themselves over the entire polyp. I would remove them at night with tweezers.

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I do have what looks like to be Astrenia Starfish. Take a look at the 4th picture in my original post. I don't think that is what is ultimately stressing my zoas, but I will start removing them tonight. I've never had any issues with these starfish before. I have had a pipe organ since April and the starfish have stayed away from it. At least in my tank.

webster1234 said:

I would wager you have zoa eating nudibranches. Do you have one of those UV flashlights? If you do, use it at night and you will see them on your zoas. They will glow like a firefly. If you don't have one of those lights, swing by and borrow mine, or you can get them online for about 20 bucks. If you find that is what you have, sucking them out with a turkey baster every night will eventually get them. They lay eggs so you have to keep at it until all the eggs have hatched. They don't mature enough to lay eggs for a few weeks so persistence will get them.

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I do have a UV flashlight. I just did an initial check and didn't see anything but I will look again tonight!

There are so many different asterIna stars so harmful some not. Maybe maybe not. I would take that suggestion about checking at night. I found a spider on a colony I bought once.


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Tstew32 said:

Have you double and triple checked your salinity? I have noticed zoas suffering from this in the past.

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I have checked my salinity but I will pull out the calibration fluid and verify my refractometer is good to go. I checked it out in April but I have not checked it recently.

Addressing water quality.

Because of the issues I've been having about a month ago I went ahead and replaced all of the filters in my RODI setup (particulate, carbon block, both membranes, and the DI) to rule that out as being an issue. I've also been doing regular weekly 20-25% water changes and this week I increased that frequency to every 3 to 4 days based on when I can get it done. I'm using Tropic Marin Pro Reef salt and make Alk, Ca, Mag, and nitrate adjustments before adding the new water. I also added the protein skimmer about 6 weeks ago as suggested in another thread as well as I used a little bit of carbon. Dropped a bag into a high flow section in my sump. I have since removed the carbon. Seems like the cleaner I make my water, the more problems I start having. Frustrating. I also bought the Triton ICP and NDOC test kits and the results came back this week. I was also going to do a complete round of testing today before I made this post but I will go ahead and include the Triton results now and post my latest test kit results later this evening.

Triton Testing Maco Elements:

Calcium: 425 ppm
Magnesium: 1342 ppm
Phosphate: 0.29 ppm

There were no smoking guns in the ICP tests or NDOC tests (Phosphates are high, but more on that later). My Calcium, Magnesium and Iodine were low, but still in a good range. I also learned that my Magnesium test kit reads about 100 ppm too high so that is good to know. Since I got these results back I've adjusted my magnesium levels back up a little bit and added a little calcium to get me close to 450. We'll see what it really is later on tonight. So, I know my phosphates have been high which is why I've been doing all of the water changes. Turns out my Hanna Phosphate checker reads substantially higher then what I got back from the ICP tests so I've ordered a calibration standard which will arrive on Monday. As far as phosphates go, they have ALWAYS been this high or higher and all of my corals were doing great until I noticed that my nitrates were really low. So I will concede that the high phosphates are a factor in all of this but I don't think the high phosphates are the root cause of what's going on with my tank. It's like there's some sort of contaminate that didn't show up in the ICP test or some sort of element that is missing that is also not showing up in the testing. I've also ordered an Alkalinity calibration standard for my Hanna checker so I will rule that out as well.

So, in summary:

My RODI is good.
My lights are only 6 months old.
Salinity is good (but I will check calibration tonight).
Trace elements look good.
Phosphates are high but corals were doing good before.
I have a grounding probe installed. Even checked for a voltage leak with my multimeter.
I will remove the starfish.
There's green stuff growing on my zoas.
Several SPS stopped extending their polyps.
Green Toadstool and Kenya tree will not extend their polyps.
All other corals (and the fish for that matter) seems to be healthy.

I know this was a super long post but please keep the suggestions coming!!

Quite the conundrum. My phosphates have been his for a long time. Fluctuates from .79 down to .17 I test phosphate almost everyday trying to find the sweet spot with the GFO I started using. I guess it could be phosphate but I haven’t had any polyps of zoas melt as of yet. My tank is almost all zoas and shrooms...


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My PO4 runs .5 on the high end and .25 on the low end. It's not your PO4.

SCUBAFreaky said:

I do have a UV flashlight. I just did an initial check and didn't see anything but I will look again tonight!

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The zoa eating critters only come out at night. If you are checking before 11pm. you might not see anything. They munch all night and sleep all day.

webster1234 said:

My PO4 runs .5 on the high end and .25 on the low end. It's not your PO4.

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James, do you mean 0.05 on the high and 0.025 on the low?

SCUBAFreaky said:

James, do you mean 0.05 on the high and 0.025 on the low?

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nope....this is today...and it actually made me happy that it was this low. It's usually higher that that.

You might also try blowing that green stuff off with a turkey baster. That can coat and irritate your corals, maybe causing them to close up.

webster1234 said:

nope....this is today...and it actually made me happy that it was this low. It's usually higher that that.

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Well, that's right where mine are based on my ICP test. Ok, I agree, it's not likely my phosphates causing this. I will look for evil critter tonight!

webster1234 said:

You might also try blowing that green stuff off with a turkey baster. That can coat and irritate your corals, maybe causing them to close up.

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I have tried that already but I was using my long stem spot feeder and not an actual turkey baster. The stuff didn't seem to budge. I will try a legitimate turkey baster this evening.