Why are my zoas melting?

[clhardy5]

So, over the last week or so, several of my zoa colonies started to melt. I have changed nothing in this tank for 6 months - no new fish, no new corals - and everything was doing great - and growing like weeds....

then, my zoas started to look bad, and several colonies have almost completely disappeared.

I do 15% water changes every two weeks.
Current parameters:
Alk 8.3 (both Hannah and Apex)
Calcium 440
Mag 1390
Ph ranges from 8.2-8.4
Nitrates 10 (Hannah)
Phosphates .15 (Hannah)
salinity 35
temp 79-80

I do two part dosing - but nothing else. All the other corals look fine - Goni's, Torches, Hammers, Frogspawn, green slimer, green goblin, leather, birds nest. The zoas aren't near any other corals - just in their zoa garden.

I put some fresh carbon in this morning just in case.

I sent an ICP test off yesterday, but I imagine it will be a bit until I get it back.

The zoas are on rather big rocks - so not practical to take out and dip.

I haven't seen any fish picking on them, and last night after lights out, I took a look with a flashlight, and didn't see anything on them either.

Any ideas?

 

[Edgecrusher28]

Any algae issues with your P04 being in that range? Do you have any palythoa species in the tank, and if so are they do better than the other Zoanthus species? Do you run a skimmer, and if so what size and for how long?

 

[Lavey29]

I was going to ask about leather corals but you run carbon. The only next thing maybe zoa eating spiders?

 

[koyfish57]

So, over the last week or so, several of my zoa colonies started to melt. I have changed nothing in this tank for 6 months - no new fish, no new corals - and everything was doing great - and growing like weeds....

then, my zoas started to look bad, and several colonies have almost completely disappeared.

I do 15% water changes every two weeks.
Current parameters:
Alk 8.3 (both Hannah and Apex)
Calcium 440
Mag 1390
Ph ranges from 8.2-8.4
Nitrates 10 (Hannah)
Phosphates .15 (Hannah)
salinity 35
temp 79-80

I do two part dosing - but nothing else. All the other corals look fine - Goni's, Torches, Hammers, Frogspawn, green slimer, green goblin, leather, birds nest. The zoas aren't near any other corals - just in their zoa garden.

I put some fresh carbon in this morning just in case.

I sent an ICP test off yesterday, but I imagine it will be a bit until I get it back.

The zoas are on rather big rocks - so not practical to take out and dip.

I haven't seen any fish picking on them, and last night after lights out, I took a look with a flashlight, and didn't see anything on them either.

Any ideas?

So, over the last week or so, several of my zoa colonies started to melt. I have changed nothing in this tank for 6 months - no new fish, no new corals - and everything was doing great - and growing like weeds....

then, my zoas started to look bad, and several colonies have almost completely disappeared.

I do 15% water changes every two weeks.
Current parameters:
Alk 8.3 (both Hannah and Apex)
Calcium 440
Mag 1390
Ph ranges from 8.2-8.4
Nitrates 10 (Hannah)
Phosphates .15 (Hannah)
salinity 35
temp 79-80

I do two part dosing - but nothing else. All the other corals look fine - Goni's, Torches, Hammers, Frogspawn, green slimer, green goblin, leather, birds nest. The zoas aren't near any other corals - just in their zoa garden.

I put some fresh carbon in this morning just in case.

I sent an ICP test off yesterday, but I imagine it will be a bit until I get it back.

The zoas are on rather big rocks - so not practical to take out and dip.

I haven't seen any fish picking on them, and last night after lights out, I took a look with a flashlight, and didn't see anything on them either.

Any ideas

I was going to ask about leather corals but you run carbon. The only next thing maybe zoa eating spiders?

 

[koyfish57]

maybe a temperature issue, 79-80 seems pretty hot to me. Maybe try walking it down to 76-78

 

[vetteguy53081]

So, over the last week or so, several of my zoa colonies started to melt. I have changed nothing in this tank for 6 months - no new fish, no new corals - and everything was doing great - and growing like weeds....

then, my zoas started to look bad, and several colonies have almost completely disappeared.

I do 15% water changes every two weeks.
Current parameters:
Alk 8.3 (both Hannah and Apex)
Calcium 440
Mag 1390
Ph ranges from 8.2-8.4
Nitrates 10 (Hannah)
Phosphates .15 (Hannah)
salinity 35
temp 79-80

I do two part dosing - but nothing else. All the other corals look fine - Goni's, Torches, Hammers, Frogspawn, green slimer, green goblin, leather, birds nest. The zoas aren't near any other corals - just in their zoa garden.

I put some fresh carbon in this morning just in case.

I sent an ICP test off yesterday, but I imagine it will be a bit until I get it back.

The zoas are on rather big rocks - so not practical to take out and dip.

I haven't seen any fish picking on them, and last night after lights out, I took a look with a flashlight, and didn't see anything on them either.

Any ideas?

Zoas are not picky but regretfully to say, often when they are melting, they are dying. It can be to too much light or water flow, sudden change of parameters and even use of vodka or carbon dosing that reduces nitrate quickly. Assure salinity and Phos has not become elevated.
This is NOT a light issue although most zoa favor low light. It is melting and a sign of stress. Oten a simple dip in Lugols iodine can perk them up. There are a number of factors why zoas close up especially water movement/flow as zoas do not require the consistent high flow conditions that SPS corals do. I would consider running moderate flow which is ideal but Zoa can adapt to low or high flow. In high flow, you will typically see polyps grow closer to the rock with shorter stalks.
Another is lack of feeding and food as infrequent feeding and low nutrients can lead to an entire colony melting down. You dont need to target feed as zoas are photosynthetic. It is generally found that target feeding zoas always provides mixed results when a food falls onto their polyps.

Back to parameters, good water quality is a must.
dKH: 8.0 - 11
Calcium: 400 - 450
Magnesium: 1300 - 1350
Iodide: Maintained via regular water changes or manually at small dosages
Temperature: 78-79 degrees
pH: 8.1-8.3
Phosphates: .04 - .08
Nitrates < 10
Temperature and pests are often blamed. Spiders although super tiny can be spotted going into heads of zoa and if you have asterina stars- they are prime suspects as are rabbitfish and butterfly fish and dwarf angels.

 

[clhardy5]

Any algae issues with your P04 being in that range? Do you have any palythoa species in the tank, and if so are they do better than the other Zoanthus species? Do you run a skimmer, and if so what size and for how long?

I do have Paly's, and they are doing fine. No melting so far. I do not have any algae issues.....I have a chaeto reactor, a reefmat and do run my skimmer 24/7 (except for about 30 minutes after feeding)

 

[clhardy5]

I was going to ask about leather corals but you run carbon. The only next thing maybe zoa eating spiders?

I didn't see any at night.....and I would wonder how they got in? Or does it take them 9 months to multiply enough to do damage?

 

[clhardy5]

maybe a temperature issue, 79-80 seems pretty hot to me. Maybe try walking it down to 76-78

I could try that....I did use to run in cooler....but then saw a video by Jake Adams saying that running in at 80 may be better...

 

[clhardy5]

Zoas are not picky but regretfully to say, often when they are melting, they are dying. It can be to too much light or water flow, sudden change of parameters and even use of vodka or carbon dosing that reduces nitrate quickly. Assure salinity and Phos has not become elevated. temperature and pests are often blamed. Spiders although super tiny can be spotted going into heads of zoa and if you have asterina stars- they are prime suspects as are rabbitfish and butterfly fish and dwarf angels.

There's been no lighting change, or water flow change over the last two years....so I'm thinking it isn't that. I do not vodka or carbon dose anymore....but I did a year ago - but the zoas were fine then. I don't have any asterna stars, or a rabbit or butterfly fish.

Salinity is stable at 35....Range has been 34.7-35.4 according to Apex....and I double checked with a refractometer and my Hannah Salinity tester.

Here is my fish list:
Lawn Mower Blenny
Powder Brown, Hippo, yellow, scopas and sailfin tang
royal gramma
Two clowns
Cleaner wrasse
Melanarus wrasse
two damsels
Mandarin goby
filefish....

All of these fish have been in the tank two years this month - except the file fish - which was added about two months ago.

I'm just at a loss.....

 

[vetteguy53081]

There's been no lighting change, or water flow change over the last two years....so I'm thinking it isn't that. I do not vodka or carbon dose anymore....but I did a year ago - but the zoas were fine then. I don't have any asterna stars, or a rabbit or butterfly fish.

Salinity is stable at 35....Range has been 34.7-35.4 according to Apex....and I double checked with a refractometer and my Hannah Salinity tester.

Here is my fish list:
Lawn Mower Blenny
Powder Brown, Hippo, yellow, scopas and sailfin tang
royal gramma
Two clowns
Cleaner wrasse
Melanarus wrasse
two damsels
Mandarin goby
filefish....

All of these fish have been in the tank two years this month - except the file fish - which was added about two months ago.

I'm just at a loss.....

As soon as i saw filefish- He jumped out at me. There are numerous posts of files eating GSP and aptasia and often a complaint with leather files who are purchased for aptasia battle and end up eating zoa instead

 

[zuri]

zoas and blastos are the trumpets to bacterial problems if I see multiple colonies in trouble, I break out the uv and begin prepping for cyano or dino's

 

[littlebigreef]

There's been no lighting change, or water flow change over the last two years....so I'm thinking it isn't that. I do not vodka or carbon dose anymore....but I did a year ago - but the zoas were fine then. I don't have any asterna stars, or a rabbit or butterfly fish.

Salinity is stable at 35....Range has been 34.7-35.4 according to Apex....and I double checked with a refractometer and my Hannah Salinity tester.

Here is my fish list:
Lawn Mower Blenny
Powder Brown, Hippo, yellow, scopas and sailfin tang
royal gramma
Two clowns
Cleaner wrasse
Melanarus wrasse
two damsels
Mandarin goby
filefish....

All of these fish have been in the tank two years this month - except the file fish - which was added about two months ago.

I'm just at a loss.....

Had no fewer than two buddies experienced file fish going rogue in the last month. Started on zoas and moved to lps. That’s likely your issue right there.

 

[ptrusk]

I would bet that the filefish is chowing down on them

 

[Edgecrusher28]

I do have Paly's, and they are doing fine. No melting so far. I do not have any algae issues.....I have a chaeto reactor, a reefmat and do run my skimmer 24/7 (except for about 30 minutes after feeding)

I have a difference of opinion here compared to the other members. However, I am going/gone through almost the exact same scenario that you are experiencing with your zoa's. For example, I have diligently gone though all of the water parameters time and time again without finding any issues. I then went down a rabbit hole of ensuring all trace elements were being auto dosed to perfection through 3 months worth of weekly ICP tests; no improvement except for LPS.SPS. Bought a PAR meter because of course that was the only thing that could make sense at this point; no improvement.

Really no matter what I did, for some reason I could not keep my Zoanthus species happy. Mind you that my Paly's were non-effected for whatever reason and I had puffy and healthy LPS and the best polyp extension on my acro's ever... I have done 3 Flux-RX treatments because why not and who knows; no improvement. I've now done two Chemi-Clean treatments because why not and who knows; no improvement. Moved troubled frags to more light, then less light, then more flow, then less flow ETC; no improvement. I've ran nitrates at 20 and phosphate at .1; no improvement, I then tried 5 nitrates and .03 phosphates; once again, no improvement.

At this point I have exhausted all of the technical solutions that one could expect to hear or be given in their attempt to find help. It is also obvious that there is no underlining issues with the core water quality when SPS,LPS are happy, colorful and growing. What I do believe is I have been over skimming my tank perhaps removing skimmable bacteria that these Zoanthus species coral require to either metabolize their energy or to perhaps keep their mats and polyps clean or protected from other bacteria. I am no only running my skimmer for a handful of hours a day mostly after feeding the tank; wish me luck.

 

[clhardy5]

I have a difference of opinion here compared to the other members. However, I am going/gone through almost the exact same scenario that you are experiencing with your zoa's. For example, I have diligently gone though all of the water parameters time and time again without finding any issues. I then went down a rabbit hole of ensuring all trace elements were being auto dosed to perfection through 3 months worth of weekly ICP tests; no improvement except for LPS.SPS. Bought a PAR meter because of course that was the only thing that could make sense at this point; no improvement.

Really no matter what I did, for some reason I could not keep my Zoanthus species happy. Mind you that my Paly's were non-effected for whatever reason and I had puffy and healthy LPS and the best polyp extension on my acro's ever... I have done 3 Flux-RX treatments because why not and who knows; no improvement. I've now done two Chemi-Clean treatments because why not and who knows; no improvement. Moved troubled frags to more light, then less light, then more flow, then less flow ETC; no improvement. I've ran nitrates at 20 and phosphate at .1; no improvement, I then tried 5 nitrates and .03 phosphates; once again, no improvement.

At this point I have exhausted all of the technical solutions that one could expect to hear or be given in their attempt to find help. It is also obvious that there is no underlining issues with the core water quality when SPS,LPS are happy, colorful and growing. What I do believe is I have been over skimming my tank perhaps removing skimmable bacteria that these Zoanthus species coral require to either metabolize their energy or to perhaps keep their mats and polyps clean or protected from other bacteria. I am no only running my skimmer for a handful of hours a day mostly after feeding the tank; wish me luck.

Hm.....I think I will try this as well. I do have a roller mat, and a skimmer running.....maybe I taking too much out. I thought that would show up in my nitrate/phosphate levels..

I'll wish you luck if you wish me luck as well!!

 

[Edgecrusher28]

Hm.....I think I will try this as well. I do have a roller mat, and a skimmer running.....maybe I taking too much out. I thought that would show up in my nitrate/phosphate levels..

I'll wish you luck if you wish me luck as well!!

I have absolutely no evidence at this point to support this statement, but I just don't believe the issue we are having is nitrate and or phosphate based. I assume you can have appropriate levels of N03,P04 yet pull out too much bacteria with super aggressive skimming. Worst case scenario is I'm wrong and I can check off one more item that didn't fix the problem and move onto the next.

Keep my posted on what you find, there is bound to be a viable solution to our problem here.

 

[littlebigreef]

I have absolutely no evidence at this point to support this statement, but I just don't believe the issue we are having is nitrate and or phosphate based. I assume you can have appropriate levels of N03,P04 yet pull out too much bacteria with super aggressive skimming. Worst case scenario is I'm wrong and I can check off one more item that didn't fix the problem and move onto the next.

Keep my posted on what you find, there is bound to be a viable solution to our problem here.

I fully suspect the file fish to be the culprit in @clhardy5's case.

Regarding @Edgecrusher28's on going issues its part of a problem that all zoa keepers with larger collections face. I'm not sure what you where targeting with the reef-flux but I've often used chemi-clean as a system-wide treatment when I get something in there bouncing around knocking out zoa colonies. It's efficacy varies greatly. You'd also mentioned testing with a par meter, what was your par in the areas you're keeping zoas? While many strains can adapt to higher par some of the strains that get labeled 'difficult' often times need a lower par that one might run in a standard reef. Hence, we run in the issue of making compromises for one coral or another in a standard reef. One other item that's quantifiable is not so much the alkalinity but the stability of it. In my previous house I had my 125 zoa tank piggy-backed on my 220 which had a lot of large sps and lps sucking alk out of the water. I dosed used a 2 part and came to find out via the trident just how much my alk was varying during the day and causing me issues. This is not something I would have necessarily figured out unless I was testing twice or three times a day on my own. If there's one thing zoas don't like its alk swings - which can be difficult to manage in a mixed reef. I now have a dedicated zoa trough split from the display and don't suffer those issues any more.

You've obviously taken an extremely pragmatic is sussing out all the potential issues and I applaud you for that.

One area touched on but not addressed in your breakdown is feeding. You experimented with running the nitrates higher and lower. How old is the system and do you target feed or broadcast feed? If so, with a Rod's food or Reef Roids like product? Over the last decade I've come to appreciate just how ravenous zoas, especially the larger ones, actually are. In a mature system fish poop and slurry from frozen foods will get the job done for many zoas. However, there's a ceiling there depending on skimming, socks, roller mat and overall nutrient export. Dripping in phyto or the weekly broadcast/targeting feeding of a prepared product has been transformative for me in getting flagging and stalling zoas 'right.'

The other area I'd like to open the conversation to is bacterial and protozan issues. I think far too often we take it for granted that observable pests, pox, nudis, spiders, are the main culprits when in reality I suspect these bacterial and protozan issues are disproportionally responsible for most zoa deaths. This is based on years and years of reading zoa forum posts and my own experience. Post move (spring '21) I've been keeping about 200 strains in my zoa trough (some have been with me 12+ years and through 3 moves/4 systems) and fairly regularly I'd have something come in on a new coral and knock out a few established frags or colonies (or the original host) before I could get it under control. Obviously this is not something that's going to show up on a test but you can tell by observation when something begins to look off. About 6 months ago I started putting every coral that goes in through QT for 9-10 weeks. I've found the results to be dramatic in regards to having zoas melt/pick up an infection. The amount of things I was actively dipping dropped from 10-12 to 5-6 to almost none. It goes without saying that proper husbandry goes a long way. I'm done doing a single Coral Rx dip and then dropping in the frag and hoping for the best. But the question remains, do these bacteria/protozans target specific coral? Or are they like ich where something can come in on a lps and jump to a zoa or sps? I don't know but I'd like to learn more. In the meantime I'm adding a Uv sterilizer based on conversation with other collectors and growers for the times when issues seem to arise out of no where.

In my final thought I'm not claiming to be bacteriologist but I've come to appreciate chemi-clean (as a dip and system wide treatment), cipro, furan-2 (you can still buy the components and make it yourself), and metroplex and how each has a varying ability to resolve issues when zoas just start melting. I've had instances where one did nothing while the other saved the day, and vise versa.

If nothing else I hope this gives you both some additional avenues to consider in figuring out what's ailing your zoas.

 

[kevgib67]

Hm, I don’t know why but sometimes zoas just melt. I have a zoa garden which started with 17 different zoa. All happy and spreading. Then I had KedsRed , bam bams, scrambled eggs and fruits loops melt over 6-7 months while all the surrounding ones have continued to thrive. I will be curious to see your iodine level when you get your test results back. Zoas tend to do poorly with low iodine.

 

[Edgecrusher28]

I fully suspect the file fish to be the culprit in @clhardy5's case.

Regarding @Edgecrusher28's on going issues its part of a problem that all zoa keepers with larger collections face. I'm not sure what you where targeting with the reef-flux but I've often used chemi-clean as a system-wide treatment when I get something in there bouncing around knocking out zoa colonies. It's efficacy varies greatly. You'd also mentioned testing with a par meter, what was your par in the areas you're keeping zoas? While many strains can adapt to higher par some of the strains that get labeled 'difficult' often times need a lower par that one might run in a standard reef. Hence, we run in the issue of making compromises for one coral or another in a standard reef. One other item that's quantifiable is not so much the alkalinity but the stability of it. In my previous house I had my 125 zoa tank piggy-backed on my 220 which had a lot of large sps and lps sucking alk out of the water. I dosed used a 2 part and came to find out via the trident just how much my alk was varying during the day and causing me issues. This is not something I would have necessarily figured out unless I was testing twice or three times a day on my own. If there's one thing zoas don't like its alk swings - which can be difficult to manage in a mixed reef. I now have a dedicated zoa trough split from the display and don't suffer those issues any more.

Thank you for your assistance and sharing your ideas. You covered a lot of things here so sorry if I miss a question you asked in your reply, but here we go. I ran the Reeflux treatments more as a lets see approach, as I have heard in the past that even small filaments of algae could irritate zoa's and prevent them from opening and maybe I had algae on them that I could not see and my CUC would not touch it. I have done two full tank Chemiclean treatments and one 5 gallon bucket treatments with a few troubled zoa's left in overnight for 24 hours. Unfortunately that was not the fix for me. I use Red Sea blue bucket salt and mix it to 1.026 which works out to be about 10.0 Dkh, which is what I hold it at with an Alk auto-doser. The tank consumes around 14.5ml per day, which is dosed 12 times throughout the day, so I'm not sure on the total swings that may be occurring.

The par on the tank varies by location as you can imagine, the highest of par readings I have where the zoa's are kept was around 205-210, and the lowest was around 80/90 on the edge of the tank where I do keep a few frag racks and Zoa's. On average I would venture to guess the PAR is around 130/160,

You've obviously taken an extremely pragmatic is sussing out all the potential issues and I applaud you for that.

One area touched on but not addressed in your breakdown is feeding. You experimented with running the nitrates higher and lower. How old is the system and do you target feed or broadcast feed? If so, with a Rod's food or Reef Roids like product? Over the last decade I've come to appreciate just how ravenous zoas, especially the larger ones, actually are. In a mature system fish poop and slurry from frozen foods will get the job done for many zoas. However, there's a ceiling there depending on skimming, socks, roller mat and overall nutrient export. Dripping in phyto or the weekly broadcast/targeting feeding of a prepared product has been transformative for me in getting flagging and stalling zoas 'right.'

Tank is 8-9 months old (100 gallon system) with skimmer and ATS and standard socks and a Pentair 25W UV. I spot feed once a week with Reef Roids and Broadcast feed once a week also with Reef Roids at night. Additionally, I will add Reef Energy once or twice a week during peak whites (no real reason, it just seems fancy),

The other area I'd like to open the conversation to is bacterial and protozan issues. I think far too often we take it for granted that observable pests, pox, nudis, spiders, are the main culprits when in reality I suspect these bacterial and protozan issues are disproportionally responsible for most zoa deaths. This is based on years and years of reading zoa forum posts and my own experience. Post move (spring '21) I've been keeping about 200 strains in my zoa trough (some have been with me 12+ years and through 3 moves/4 systems) and fairly regularly I'd have something come in on a new coral and knock out a few established frags or colonies (or the original host) before I could get it under control. Obviously this is not something that's going to show up on a test but you can tell by observation when something begins to look off. About 6 months ago I started putting every coral that goes in through QT for 9-10 weeks. I've found the results to be dramatic in regards to having zoas melt/pick up an infection. The amount of things I was actively dipping dropped from 10-12 to 5-6 to almost none. It goes without saying that proper husbandry goes a long way. I'm done doing a single Coral Rx dip and then dropping in the frag and hoping for the best. But the question remains, do these bacteria/protozans target specific coral? Or are they like ich where something can come in on a lps and jump to a zoa or sps? I don't know but I'd like to learn more. In the meantime I'm adding a Uv sterilizer based on conversation with other collectors and growers for the times when issues seem to arise out of no where.

In my final thought I'm not claiming to be bacteriologist but I've come to appreciate chemi-clean (as a dip and system wide treatment), cipro, furan-2 (you can still buy the components and make it yourself), and metroplex and how each has a varying ability to resolve issues when zoas just start melting. I've had instances where one did nothing while the other saved the day, and vise versa.

If nothing else I hope this gives you both some additional avenues to consider in figuring out what's ailing your zoas.