Zoas shrinking, melting and dying

[Bars]

As the title says. I bought a colony of +/- 60 polyps when I started the tank. They slowly started shrinking and melting. That colony is completely gone now. Every other frag I got after that is doing the same: looking good for a while, then shrinks, melts and eventually dies. In addition to that my gold zoas' polyps look like a deformed mess. Haven't seen any growth whatsoever. Also something I noticed: each individual head seems to be sliding off the little rock they came on, attach to my liverock and then still die.

I've tried placing them at several spots: near the surface with high flow and medium flow, near the substrate with high flow and medium flow, halfway with high flow and medium flow. I try spot feeding them reef roids weekly. They respond to it, but I'm not sure if they're eating it or get agitated. Nothing seems to work.

As far as I can tell there's no pests on them, although I haven't looked underneath the frags.
No fish or invertebrates bothering them either.

Parameters as of today:
Kh: 9.6
Calc: 435
Mg: 1290 (usually higher, around 1400)
NO3: 10
PO4: 0,05

I'm doing bi-weekly water changes, no dosing (yet). My lfs recommended to start dosing amino acids for my buttons, so I've started doing that last week.
Everything else in the tank (mostly lps), except for my acans, are doing great. Maybe or maybe not related: I can't keep gsp or xenia alive either. They start opening after about a week and then melt away.

Any thoughts? I've eventually just given up on them, but I still like to have some nice zoa covered rocks.

 

[Sean Duggan]

Zoas don’t need a medium to high flow. I’ve always kept mine in low or medium. Also what fish and inverts do you have in tank. It’s possible something is eating it

 

[Bars]

I have 4 cleaner shrimp (2 skunk, 2 fire), a pair of percula clowns, tailspot blenny and yellowtail blenny. 3 red hermits, 2 black hermits, 2 conches, couple of Astrea snails, lots of nassarius snails, lots of small round snails with black/deep purple lines on their shells and quite a lot of Asterina stars.

And, I assume, lots of copepods. These are red though. Before I moved 2 months ago I only ever saw grey/transparant pods, fair bit larger than these red ones as well.

The blennies haven't been in the tank long though, problems started way before I got them.

 

[Sean Duggan]

A lot of people have made claims that Asterina stars eat zoanthids. And if you have quite a lot like you said it is possible that they’re the culprit. Seems like you have a smaller tank too with a lot of inverts so more competition for food and that can also lead to the consumption of zoas by the stars. Also check your iodine reading, that could possibly be a problem but I doubt it would make you lose whole colonies.

 

[ScottB]

Asterinas: when I had some, they never bothered zoas. By the time I had a ton of them, they were crawling all over my zoas. At least the expensive ones. I spent hours tweezing them out of 100 lbs of rock to get them under control.

I would recommend pulling a couple colonies out for inspection with light & magnification and a strong dip. See if you can loosen up or kill off any critters.

 

[Bars]

^ Any tips for dipping? Never done that before and not sure what to use. I'll try to pull the worst looking frags out to get a closer look.

As for the stars, I've never seen them on or near the zoas. During the day or when lights are off. Would they be able to eat healthy zoas? Obivously not so healthy anymore, but I assume they were when I bought them.

Also, all of these zoas have been in the tank for at least 4 months. They've been slowly getting worse. If something would be eating them, wouldn't they die quicker?

 

[Sean Duggan]

I personally use coral RX Pro, great did in my opinion. If you have never dipped before it is possible that you might have a zoa eating spider or nudibranch. These pests won't instantly wipe out a colony but slowly wither it down.

 

[Bars]

Alright thanks, I'll pick that up tomorrow. Never took such pests in consideration because I never saw anything on them.

 

[ScottB]

Not to plug CoralRX, but when I say strong dip, that is what I think of. It can be tough on some acros, but safe for zoas. Once in the dip, blast the colony like crazy with a turkey baster.

Spider and nudis are difficult to see on and within the colony. Dip in a shallow glass bowl so you can see what you have. Couple pics for you:

Zoanthid Eating Spiders - Coral Rx Don't Risk It Dip It!

Sea Spiders are not spiders in the traditional sense. They are not members of the arachnid family, but are, instead, marine arthropods known as pycnogonids.

coralrx.com

Zoanthid Eating Nudibranchs - Coral Rx Don't Risk It Dip It!

Zoanthid Eating Nudibranchs also are known as Zoa Eating Nudibranchs or Zoo Eating Nudibranchs are a type of aeolid nudibranchs which are known to feed on

coralrx.com

 

[ScottB]

^ Any tips for dipping? Never done that before and not sure what to use. I'll try to pull the worst looking frags out to get a closer look.

As for the stars, I've never seen them on or near the zoas. During the day or when lights are off. Would they be able to eat healthy zoas? Obivously not so healthy anymore, but I assume they were when I bought them.

Also, all of these zoas have been in the tank for at least 4 months. They've been slowly getting worse. If something would be eating them, wouldn't they die quicker?

For the most part they just eat detritus and are harmless. I never had a problem until they got way out of hand. Or at least a species of the asterinas got out of hand.

As this population explosion peaked, I was seeing my tubbs zoas stayed closed up. Often. I inspected and pulled off 5-6 asterinas and they had a definite BLUE color to them. Caught them "blue-handed". I then got serious about removing them several evenings in a row. Happy Tubbs and Rastas since then.

 

[Bars]

Just removed the plugs from the liverock for a closer look. Unfortunately I don't have a magnifying glass so couldn't really see anything. Just a few tiny, tiny snails on the gold zoas, 1 asterina and lots of pods.

I also noticed some long, really thin worms inside the gold zoas. They were moving.

Also took 2 more pictures of 2 frags that I assume are dead. Previous frags eventually looked like that as well.

 

[45ZoaGarden]

I wouldn’t dip them. Pointless in my opinion. Wait till the lights go off at night and check them out. Hermits and cleaner shrimp are evil. Im willing to bet the shrimp is eating them.

 

[45ZoaGarden]

They’re not dead yet. They should come back. Zoas are hard to get rid of. I can give Mohawks everything I have to get them off a rock and a week later the rock is covered again LOL

 

[45ZoaGarden]

Best way to get rid of pests isn’t to dip your corals in chemicals. Get a natural predator that’s always hunting for them such as wrasses. I’ve also heard sexy shrimp destroy pretty much every ugly critter I don’t wanna see

 

[Terry Mattson]

Make sure you have iodine at about. 05 or .06 ppm. Iodine was my issue. You can test your it with a red sea iodine test lit. I use brightwell iodine. My zoas, about 100, just would not open. Iodine was very low. Added a few drops and next day all opened. And now they are healthy growing, spreading....

 

[ScottB]

Best way to get rid of pests isn’t to dip your corals in chemicals. Get a natural predator that’s always hunting for them such as wrasses. I’ve also heard sexy shrimp destroy pretty much every ugly critter I don’t wanna see

I will second your suggestion about predators. I keep several wrasses in every tank and they are murderous hunters. When I baste colonies, they are johnny-on-the-spot and hit anything that comes out.

As to the chemicals, well a certain handful are fairly necessary as every professional aquaculturist will tell you. With thousands of hours and dollars invested, it is smart to research the risks and rewards.

Most dips are just concentrations of natural things like tea tree oil and citronella although I find it annoying that few/no suppliers actually will list all the ingredients.

 

[45ZoaGarden]

I will second your suggestion about predators. I keep several wrasses in every tank and they are murderous hunters. When I baste colonies, they are johnny-on-the-spot and hit anything that comes out.

As to the chemicals, well a certain handful are fairly necessary as every professional aquaculturist will tell you. With thousands of hours and dollars invested, it is smart to research the risks and rewards.

Most dips are just concentrations of natural things like tea tree oil and citronella although I find it annoying that few/no suppliers actually will list all the ingredients.

The not listing what it actually is keeps me away. I have too much invested to risk a bad chemical killing my corals. I can deal with critters. Chemicals are silent coral killers. Back in the day, cross contamination from a bucket that my wife used to clean the floors that I later used to do a water change killed my whole 250 gallon African cichlid tank. I woke up one morning and everything was floating.

 

[ScottB]

The not listing what it actually is keeps me away. I have too much invested to risk a bad chemical killing my corals. I can deal with critters. Chemicals are silent coral killers. Back in the day, cross contamination from a bucket that my wife used to clean the floors that I later used to do a water change killed my whole 250 gallon African cichlid tank. I woke up one morning and everything was floating.

The new sunscreens are the silent coral killers of the current time IMO. Oxybenzone has been proven. All the benzones are suspect.

But CoralRX, Revive, etc have proven efficacy and when used properly to be safe for most corals. We can argue about Bayer, but at least we know what is in it This for another thread though.

Chemical surfactants and solvents used for cleaning floors we don't need to talk about. I am with you.

 

[45ZoaGarden]

The new sunscreens are the silent coral killers of the current time IMO. Oxybenzone has been proven. All the benzones are suspect.

But CoralRX, Revive, etc have proven efficacy and when used properly to be safe for most corals. We can argue about Bayer, but at least we know what is in it This for another thread though.

Chemical surfactants and solvents used for cleaning floors we don't need to talk about. I am with you.

Hahaha, bleach works well to get rid of wanted fish. Trust me

 

[45ZoaGarden]

Or an entire wanted aquarium LOL