Help! Setosa suddenly dying??

[CampAquarium]

Help! We have a huge setosa that is a real showpiece in our tank. Last night, I noticed a concerningly large section is dying off, and it's happening quickly. (Honestly, it either happened like within a day, or I'm somehow just completely blind considering I sit and just watch our tank every day.)

I noticed a rogue firework clove polyp peeking out from under the section, and used tweezers to remove it right away. It had already grown a couple branches underneath the setosa. Watching it today the die-off is still growing, and alarmingly fast. See the photos below where you can see how it progressed over the last 24 hours.

Anyway, can a single clove polyp actually cause this much damage?? Can I do anything to stop the death from spreading? And should I do anything to the part that has already died? Is this normal, or is something else likely wrong?

1) This is last night, where you can see the offending clove polyp.

2) This was this morning. Polyp removed, but the dead section had grown to about 1.5 inches across.

3) And this was this evening. The dead section has expanded further up and out.

Our parameters:
Temp: 77.5
Salinity: 1.024
Calcium: 409
Magnesium: 1510
Alk: 8.1
Ph: 8.0
Nitrates: 1.8
Phosphates: 0.07

 

[Reefer Matt]

I'd check for montipora eating nudibranchs underneath it. The dead section can be broken off to check. They are little white critters. I doubt clove polyp had any effect.

 

[19Mateo83]

Look for these…. Monti eating nudibranch

 

[CampAquarium]

Look for these…. Monti eating nudibranch

Oh man, I hope it's not that, but you're definitely right that I should check. Do you know if I should wait until nighttime to break off a piece and look? Or does it not matter with these guys.
Thanks for the photos too, super helpful.

 

[19Mateo83]

Do you have the option to dip it?

 

[CampAquarium]

Do you have the option to dip it?

Unfortunately it's pretty solidly encrusted. If dipping it is the only option, I'd have to find a way to break it off

 

[19Mateo83]

Let me see if I can summon someone with more experience, @vetteguy53081

 

[vetteguy53081]

Help! We have a huge setosa that is a real showpiece in our tank. Last night, I noticed a concerningly large section is dying off, and it's happening quickly. (Honestly, it either happened like within a day, or I'm somehow just completely blind considering I sit and just watch our tank every day.)

I noticed a rogue firework clove polyp peeking out from under the section, and used tweezers to remove it right away. It had already grown a couple branches underneath the setosa. Watching it today the die-off is still growing, and alarmingly fast. See the photos below where you can see how it progressed over the last 24 hours.

Anyway, can a single clove polyp actually cause this much damage?? Can I do anything to stop the death from spreading? And should I do anything to the part that has already died? Is this normal, or is something else likely wrong?

1) This is last night, where you can see the offending clove polyp.

2) This was this morning. Polyp removed, but the dead section had grown to about 1.5 inches across.

3) And this was this evening. The dead section has expanded further up and out.

Our parameters:
Temp: 77.5
Salinity: 1.024
Calcium: 409
Magnesium: 1510
Alk: 8.1
Ph: 8.0
Nitrates: 1.8
Phosphates: 0.07

These are generally hardy
Your mag is somewhat elevated, salinity can go up to 1.025-1.026, medium light, moderate flow, and nitrates a little low.
When they bleach like this, often low salinity, low alk and temperature too warm

 

[ninjamyst]

I lost an entire colony for no reason. But a frag on the other side of the tank wasn't affected. My guess is bacterial infection. It happened over 2 days and entire colony was gone. Good luck with yours. It doesn't look too bad and doesn't look like it's spreading.

 

[CampAquarium]

These are generally hardy
Your mag is somewhat elevated, salinity can go up to 1.025-1.026, medium light, moderate flow, and nitrates a little low.
When they bleach like this, often low salinity, low alk and temperature too warm

Thanks for the response! Yeah, we are trying to bring down the mag slowly. The dosing pump has been off recently trying to let it fall. Lighting and flow have not changed recently, and temp is steady between 77-78.

1.024 is where our salinity usually is, sometimes coming up to 1.025 periodically. I would be surprised if that were the cause as the setosa has been doing amazingly well in those conditions for about 9 months until now. It's grown super fast, solidly encrusting to the rock below and around it.

Is there anything you recommend for treatment/recovery, or to stop the spread? Like turning down the lights, a water change, or feeding/providing extra nutrients to help it fight? I did not find any nudibranchs that I could see (but will keep looking each night), and trying to remove it to dip would 100% mangle it/leave chunks behind.

 

[CampAquarium]

I lost an entire colony for no reason. But a frag on the other side of the tank wasn't affected. My guess is bacterial infection. It happened over 2 days and entire colony was gone. Good luck with yours. It doesn't look too bad and doesn't look like it's spreading.

Oh no! That's heartbreaking. I'd be so sad to lose all of ours. It's about 10 inches wide, so it's a real centerpiece in our reef.

The bleached part is definitely still growing, it's gone from about 1 inch across 36 hours ago to 3 inches across today. I hope it's slowing down, but it's scary to watch. It's our only setosa, but we have 3 cap montis that still look fine (fingers crossed).

 

[CampAquarium]

Let me see if I can summon someone with more experience, @vetteguy53081

Look for these…. Monti eating nudibranch

Ok, I broke off the bleached piece last night and inspected it for nudibranchs/eggs. Unless these things are even tinier than I think they are, I didn't see anything that obviously resembled them. Tbh, it was somewhat tricky due to the fact that this edge of the setosa had grown down to be touching the sand bed, so there was some debri and it was hard to distinguish. Also had a couple baby stomatellas hanging on.

I'll keep watching the affected area at night to see if I spot any. Would they likely be around the edges of the bleached spot? The way it's encrusted, I can't see up underneath it.

 

[ninjamyst]

Are you able to frag off a small piece just in case? The colony I lost was over 10 inches too. It sucks.

 

[vetteguy53081]

Thanks for the response! Yeah, we are trying to bring down the mag slowly. The dosing pump has been off recently trying to let it fall. Lighting and flow have not changed recently, and temp is steady between 77-78.

1.024 is where our salinity usually is, sometimes coming up to 1.025 periodically. I would be surprised if that were the cause as the setosa has been doing amazingly well in those conditions for about 9 months until now. It's grown super fast, solidly encrusting to the rock below and around it.

Is there anything you recommend for treatment/recovery, or to stop the spread? Like turning down the lights, a water change, or feeding/providing extra nutrients to help it fight? I did not find any nudibranchs that I could see (but will keep looking each night), and trying to remove it to dip would 100% mangle it/leave chunks behind.

Perhaps shut off dosers and dose manually if needed for a week and see how much drop you notice
Assure also that you’re not getting false readings

 

[CampAquarium]

Are you able to frag off a small piece just in case? The colony I lost was over 10 inches too. It sucks.

That's a good idea. If this keeps progressing, I'll definitely do that.

 

[CampAquarium]

@vetteguy53081 @19Mateo83
Thanks again for your help.

Figured I’d keep posting detailed progress here in case anyone else has this issue and they can see how things worked out.

The setosa tissue death continued to spread. I went in to our local shop, (which luckily enough is nationally-renowned for their expertise in corals). They tested our water with a fancier machine, and the levels came back pretty close to what I originally posted, but with mag in an actually normal range. So that’s good!

When I got home, after breaking off a bit more of the dead section, I was amazingly able to get my hand under the setosa and break it off the rock, with (relatively) minimal damage! I was shocked and happy!

Since I was able to remove it, I did these 6 things per our coral shop’s recs:

1) Flip it over and inspect the bottom for pests. I did not see anything unusual.

2) Trim off what I could of the dead section, cutting into the healthy flesh by about 1/2 inch all the way around, though the skeleton was too thick to cut through in one place. This ended up removing about 1/3 of the setosa’s overall size.

3) Dip the entire coral in Reef Primer for 5 min, keeping the water agitated and flowing over and through the setosa’s layers the whole time. This process flushed out about 10 brittle starfish and one unnervingly long bristleworm.

4) Use reef-safe glue to draw a thick line at the edge of where I trimmed, and in areas where I was unable to trim— draw the glue barrier where the healthy tissue meets the sick tissue. Note that “sick tissue” in this case means any tissue that is starting to look faded or brown, not just the part that had already died and peeled back. This is meant to act as a barrier, sort of like a wildfire break.

5) Adjust the placement of the setosa when i put it back in the tank, so that it’s not touching the sand bed. (It had grown down over its rock to touch the sand previously, and the problem began in one of the places where it was touching the sand.)

6) Raise our salinity slightly. The setosa is so large that I had to remove about 3 gallons of water in order to fully submerge it during the dip, so I replaced those 3 gallons with extra super salty water.

As of this morning, the STN has not progressed past the glue barrier line. Fingers crossed, and I’ll update again in a few days!

As a note, the corals shop said they had dealt with one case of STN where a private client had a giant setosa that was completely encrusted in the center of their rockwork and was impossible to remove. They used disposable reef glue tubes to make the “firewall barrier” on the setosa without removing it or cutting it up, and it worked! They even said that eventually the healthy tissue grew over the glue and covered the dead spots back up again.

 

[arnavfactoryfishtanks]

That's great to hear that you were able to get professional advice and take decisive action to help your setosa.
Following the shop's advice and going through those steps was a top-notch move. That glue barrier trick is a real game changer.

As for the critters you found during the dip, those brittle starfish and that bristleworm are typically harmless roommates. But hey, better safe than sorry, right?

The salinity adjustment was another smart move. Corals can be a bit finicky with salinity, so a slight bump could make a difference. Just remember to keep a close eye on your water parameters in the next few days since you've made some tweaks, I'm sure you know that already.

One thing that caught my eye was the sand bed issue. Sand can sometimes be a sneaky host for bacteria that aren't too friendly to corals. In the future, it might be worth considering giving corals a little elevation, like placing them on rocks or other structures.

A deep sand bed (DSB), roughly 4-6" deep, can form an anoxic zone that sustains anaerobic bacteria. This bacteria helps reduce nitrate in the tank. In contrast, a shallow sand bed, typically less than 3", doesn't support the growth of these beneficial bacteria. Instead, if not regularly cleaned or vacuumed, it can rot, leading to the growth of harmful bacteria and algae. Disturbing a mature DSB can also cause a mass die-off of the beneficial bacteria, leading to a rotting and stinking sand bed.

So, if your setosa was touching the sand, and the sand bed wasn't properly maintained, it could have introduced harmful bacteria to the coral, leading to tissue necrosis. Remember, it takes about a month or more for a healthy bacterial community to establish in a DSB, and during this time, it's best not to disturb it.

The sulfur dioxide byproduct from anaerobic bacteria in deeper sand beds can also be harmful. If you've got a deep sand bed, it's recommended to stir the substrate to degas it once or twice a month to prevent buildup of harmful gases. A remote DSB in a sump is another solution to avoid this danger, as any gases can bubble up to the surface without harm to the livestock.

Keep a keen eye on the sand bed condition and manage it properly based on its depth. This way, you can maintain a healthy environment for your corals, and hopefully prevent future issues.

I've got to say, you're really going the extra mile for your setosa and it shows. I'm rooting for its recovery! Keep us in the loop on how it's doing!

 

[19Mateo83]

Hopefully this stops the rtn and it makes a recovery. Setosa is such a pretty coral

 

[Dburr1014]

One thing that caught my eye was the sand bed issue. Sand can sometimes be a sneaky host for bacteria that aren't too friendly to corals. In the future, it might be worth considering giving corals a little elevation, like placing them on rocks or other structures.

A deep sand bed (DSB), roughly 4-6" deep, can form an anoxic zone that sustains anaerobic bacteria. This bacteria helps reduce nitrate in the tank. In contrast, a shallow sand bed, typically less than 3", doesn't support the growth of these beneficial bacteria. Instead, if not regularly cleaned or vacuumed, it can rot, leading to the growth of harmful bacteria and algae. Disturbing a mature DSB can also cause a mass die-off of the beneficial bacteria, leading to a rotting and stinking sand bed.

So, if your setosa was touching the sand, and the sand bed wasn't properly maintained, it could have introduced harmful bacteria to the coral, leading to tissue necrosis. Remember, it takes about a month or more for a healthy bacterial community to establish in a DSB, and during this time, it's best not to disturb it.

The sulfur dioxide byproduct from anaerobic bacteria in deeper sand beds can also be harmful. If you've got a deep sand bed, it's recommended to stir the substrate to degas it once or twice a month to prevent buildup of harmful gases. A remote DSB in a sump is another solution to avoid this danger, as any gases can bubble up to the surface without harm to the livestock.

Keep a keen eye on the sand bed condition and manage it properly based on its depth. This way, you can maintain a healthy environment for your corals, and hopefully prevent future issues.

This is my first time hearing any of this.

How can a dsb grow bad bacteria and not good bacteria? As I know, the entire ocean is a dsb. That would mean... Nothing can live in the ocean??

I also know sulfer dioxide bubbles harmlessly out of the tank and into the air. It is the final product of a 'cycle'.


Can you site these please so I can read up on this?

 

[arnavfactoryfishtanks]

Of course good questions,
1. DSBs and Bacteria: DSBs mainly host "good" bacteria that aid in nitrate reduction. But without proper care, harmful bacteria can increase, especially if the bed is disturbed.
2. Ocean vs Aquarium: The ocean is a vast, self-balancing ecosystem, while an aquarium is a smaller, closed system that requires meticulous balance and small changes can lead to larger impacts (that's why bigger tanks are generally more stable).
3. Sulfur Dioxide: While it typically bubbles out (as it should), in DSBs, gas pockets can form and if released suddenly, they can disrupt water chemistry.

For further reading, I'd recommend "The Reef Aquarium: Volume Three" by Sprung and Delbeek and "Aquarium Corals: Selection, Husbandry, and Natural History" by Borneman.