HELP - Sick Turbastrea Colony

[SFMAquariums]

Hello,

I just posted this in the sick fish forum bur wasn’t sure if this was the more appropriate forum & am quite worried so figured id cross post in the hopes of expediting an answer.

I have a beautiful Turbastrea sun coral colony that was one of the first additions to my ~225 gallon mixed reef tank. My tank has been running for 6-7 months now.

It appeared to be doing fantastic at first & we were target feeding it with mysis daily. For the last few days, the polyps have not been opening like they usually do & I haven’t been able to target feed it. Yesterday, I noticed that one of the polyps on the back/side of the colony seemed to be retracting & exposing the skeleton. I therefore took the coral out to perform a coral dip & realized that the backside of the coral (hidden from view) has more polyp retraction than I realized with exposed skeleton, but has also developed a black matt that is kinda soft/spongy to the touch.

I did some research & based off that, completed the coral dip. I then tried to gently scrub away some of the black matt with a soft bristle toothbrush but there was no noticeable effect. I took some pictures & returned the coral to my tank. I checked a few hours later & this morning - polyps have remained mostly closed.

I’m worried that it has developed some type of infection secondary to either improper water parameters or (more likely) cold shock - preceding all of this (1-2 weeks ago), my partner tried to do a water change & accidentally dropped the water temperature suddenly. After this we lost our decorator crab & an urchin, which then led to some parameter spikes in phosphate/nitrates which we have been trying to manage. My theory being that either the cold shock/parameter change caused death of some of the coral tissue on the back of the colony that I didn’t notice & that tissue has now become infected.

Does this seem reasonable? Does anybody have other theories? Any recommendations for next steps in terms of treatment?

Any advice would be greatly appreciated. It’s been a rough few weeks in our tank - losing our favourite decorator crab & another urchin. This is one of our favourite corals & we would hate to lose it.

Thanks!

 

[Firefish89]

Was the black matt originally polyps? In other words, did the black matt consume the polyps (or did the previously healthy polyps become the black matte)? You could try something drastic like removing the black matt with a Dremel or tougher tool. Or chisel the colony "in half" and discard the spongy stuff and reattach the coral. I would check water parameters too. I love sun corals and I find they stop opening when water parameters are off (including nitrate, phosphate, and magnesium).

 

[EnterName]

Looks like a black sponge that aggressively overgrows corals.

Physical removal of sponges is really difficult. Sponges have unbelievable regenerative capabilities that are starting immediately after getting damaged. They are so fast that you can see the regeneration happen live under a microscope. You can check out post #82 and #83 of my microscopy thread, where I explain (and show) roughly how this works.

If a few cells manage to land somewhere in your tank, they can fully rebuild a functioning sponge. The risk is low if you leave it alone, but if you start scraping it off, you should do so outside of the tank and rinse the frag carefully afterwards just to be safe.

I personally would try to treat the residues after manual removal with something like a dilute muriatic acid or hydrogen peroxide. This has two effects:

1. It kills sponge cells that could otherwise try to recover.
2. It creates air bubbles within the sponge which can cause it to starve. Sponges are filter feeders and rely on water being able to flow through them. Bubbles can block their filtration pathways and effectively let the sponge starve to death over time.

Some of the sponge is very close to polyps so the treatment will be quite dangerous and you might lose more polyps. Maybe cutting off a part of the frag is the easier (and saver) approach. Maybe you can simply take out the frag and dry the sponge with some paper towels really well to encourage air bubbles to form in it. This could stop it from growing further, but I don't know if it can spread when dying.

 

[SFMAquariums]

Was the black matt originally polyps? In other words, did the black matt consume the polyps (or did the previously healthy polyps become the black matte)? You could try something drastic like removing the black matt with a Dremel or tougher tool. Or chisel the colony "in half" and discard the spongy stuff and reattach the coral. I would check water parameters too. I love sun corals and I find they stop opening when water parameters are off (including nitrate, phosphate, and magnesium).

I don’t believe so - from what I remember, when I initially got the coral it was asymmetrical in terms of there being more polyps on the front & more of a “bare patch” on the back.

I think what has happened (to the best of my knowledge) is that:
-There has recently been some tissue/polyp recession. I am pretty confident in this as there is one polyp in particular that is showing evidence of tissue recession (see picture).
-The bare area/black matt has increased in size & is now more noticeable

As another poster after you stated, I am wondering if the black Matt is a sponge. My theory is that my recent issues with the temperature drop, subsequent livestock deaths & parameter issues has led to the sun coral becoming stressed, not opening/eating as usual & subsequent tissue/polyp recession. The sponge has then taken advantage of the available space on the frag & has expanded/become more noticeable. Does this seem reasonable?

 

[SFMAquariums]

Looks like a black sponge that aggressively overgrows corals.

Physical removal of sponges is really difficult. Sponges have unbelievable regenerative capabilities that are starting immediately after getting damaged. They are so fast that you can see the regeneration happen live under a microscope. You can check out post #82 and #83 of my microscopy thread, where I explain (and show) roughly how this works.

If a few cells manage to land somewhere in your tank, they can fully rebuild a functioning sponge. The risk is low if you leave it alone, but if you start scraping it off, you should do so outside of the tank and rinse the frag carefully afterwards just to be safe.

I personally would try to treat the residues after manual removal with something like a dilute muriatic acid or hydrogen peroxide. This has two effects:

1. It kills sponge cells that could otherwise try to recover.
2. It creates air bubbles within the sponge which can cause it to starve. Sponges are filter feeders and rely on water being able to flow through them. Bubbles can block their filtration pathways and effectively let the sponge starve to death over time.

Some of the sponge is very close to polyps so the treatment will be quite dangerous and you might lose more polyps. Maybe cutting off a part of the frag is the easier (and saver) approach. Maybe you can simply take out the frag and dry the sponge with some paper towels really well to encourage air bubbles to form in it. This could stop it from growing further, but I don't know if it can spread when dying.

I did some more research after posting last night & this is actually what I am starting to suspect (as I just outlined in response to another poster).

I think the sun coral is stressed from the recent temperature/parameter issues - lack of normal feeding behaviour, evidence of tissue recession. The sponge has then taken advantage of the tissue recession & is expanding/growing into the available space.

You seem to have a decent amount of experience/knowledge in terms of sponges - do you think further intervention is necessary at this point? My initial plan after the coral dip yesterday was to monitor the coral, trend its progress daily & focus on getting my parameters back to a stable baseline in the hopes that the polyps will start opening again, it will start eating & the tissue recession will stop.

Having said that, you mentioned these black sponges can be quite aggressive which concerns me. I had read about doing a dilute hydrogen peroxide treatment but wanted to post here before taking any drastic steps. Would you recommend going ahead with this step? I imagine I would need to use a scalpel blade or exacto knife to scrape the sponge off. Would i then just drip the hydrogen peroxide treatment onto the remaining sponge tissue? Sounds like ideally I would getting the peroxide on the sun coral?

Thanks so much for your response & insight. I very much appreciate it!

 

[EnterName]

Looks like a black sponge that aggressively overgrows corals.

Physical removal of sponges is really difficult. Sponges have unbelievable regenerative capabilities that are starting immediately after getting damaged. They are so fast that you can see the regeneration happen live under a microscope. You can check out post #82 and #83 of my microscopy thread, where I explain (and show) roughly how this works.

If a few cells manage to land somewhere in your tank, they can fully rebuild a functioning sponge. The risk is low if you leave it alone, but if you start scraping it off, you should do so outside of the tank and rinse the frag carefully afterwards just to be safe.

I personally would try to treat the residues after manual removal with something like a dilute muriatic acid or hydrogen peroxide. This has two effects:

1. It kills sponge cells that could otherwise try to recover.
2. It creates air bubbles within the sponge which can cause it to starve. Sponges are filter feeders and rely on water being able to flow through them. Bubbles can block their filtration pathways and effectively let the sponge starve to death over time.

Some of the sponge is very close to polyps so the treatment will be quite dangerous and you might lose more polyps. Maybe cutting off a part of the frag is the easier (and saver) approach. Maybe you can simply take out the frag and dry the sponge with some paper towels really well to encourage air bubbles to form in it. This could stop it from growing further, but I don't know if it can spread when dying.

I did some more research after posting last night & this is actually what I am starting to suspect (as I just outlined in response to another poster).

I think the sun coral is stressed from the recent temperature/parameter issues - lack of normal feeding behaviour, evidence of tissue recession. The sponge has then taken advantage of the tissue recession & is expanding/growing into the available space.

You seem to have a decent amount of experience/knowledge in terms of sponges - do you think further intervention is necessary at this point? My initial plan after the coral dip yesterday was to monitor the coral, trend its progress daily & focus on getting my parameters back to a stable baseline in the hopes that the polyps will start opening again, it will start eating & the tissue recession will stop.

Having said that, you mentioned these black sponges can be quite aggressive which concerns me. I had read about doing a dilute hydrogen peroxide treatment but wanted to post here before taking any drastic steps. Would you recommend going ahead with this step? I imagine I would need to use a scalpel blade or exacto knife to scrape the sponge off. Would i then just drip the hydrogen peroxide treatment onto the remaining sponge tissue? Sounds like ideally I would getting the peroxide on the sun coral?

Thanks so much for your response & insight. I very much appreciate it!

Even a stressed coral has stinging cnidocytes and produces mucus that should keep a sponge from growing over it. If all it takes is a slightly stressed coral to start taking over this is a dangerous sign. The fact that it apparently grows quite fast is another bad sign. I have not yet seen a beneficial black sponge (doesn't mean they don't exist), but I would try to get rid of it to be safe.

You can try to drip the hydrogen peroxide on the sponge or use a toothbrush to apply it. A combination of both might work best. It will be very difficult not to accidentally get some onto the polyps, but I don't have a better idea to be honest.

Please wear gloves and eye protection during the process. Sponges are known to produce toxins and I don't know how problematic these can get when cutting the sponge. The peroxide might also fly around when applied with a toothbrush.