Systemic coral death, HELP

[SeamusHarper]

In a span of a week, many of my corals have died suddenly.

Last week, a giant torch that has been in the tank for over 4 months died within three days, losing many tentacles a day, leaving only a brown stump.

My hammer coral followed the same process a few days later and now it's gone.

This morning I awoke to find the skin peeling off my Jack O Lantern, exposing white skeleton below. I also noticed a small white worm travelling along the edge so perhaps this is the culprit?

I'm also noticing webbing hanging off some of the corals, I have no idea what's going on!

Nothing has been added to the tank for over 2 months.

Temp: 77-78

Ammonia: 0 ppm

Nitrite: 0 ppm

Nitrate: ~20 ppm

pH: 8.2

Alkalinity: 9 dKH

Calcium: 400 ppm

Magnesium: 1,200 ppm

Salinity: 1.025

 

[EnterName]

If you have photos of the issue or the whole tank this could help the community to help you
Turn off the heavy blue lights and use neutral/white light if you take photos, this usually helps to keep things visible.


As for the white worm, it's hard to tell without images, but many organisms will simply profit from the biofilm that establishes when corals die, so it might just be something that helps to clean up the dead tissue.

Phosphate, flow, and light are the next potential candidates to check, and finally an ICP-MS test would help to find out if something like copper or zinc got into your tank. There are obviously more dangerous substances, but those can be introduced quite easily and are extremely toxic to corals.

 

[SeamusHarper]

Here is the Jack this morning

 

[EnterName]

(Ex)aiptasia can hurt corals and "walk" so this obviously can cause tissue necrosis, but then the edges of the coral would be hurt, not something in the middle.

That guy however, looks a bit more suspicious. I can't identify it properly, but maybe, that's the issue.

 

[SeamusHarper]

I haven't observed the (Ex)aiptasia moving, it's been stuck to that coral since it was placed in the tank months ago from what I have seen (it may be moving around and returning to it's spot I suppose). Should I remove it?

The worm disappeared shortly after I took the picture unfortunately.

 

[EnterName]

I haven't observed the (Ex)aiptasia moving, it's been stuck to that coral since it was placed in the tank months ago from what I have seen (it may be moving around and returning to it's spot I suppose). Should I remove it?

The worm disappeared shortly after I took the picture unfortunately.

They can move but don't have to. It's probably sitting still there and doesn't move.
These are still pests that can take over the entire tank and need to be treated properly to avoid them from spreading.

Don't scrape it off, they can regrow from small fragments of pedal tissue so scraping them can spread them. If you can take out the rock it's sitting on for an appropriate treatment I would advise to do so. You can use dedicated products like Aip-Away, Elimi-Aiptas, Aiptasia-X, and others to dissolve the anemone. Then rinse the spot thoroughly and return the rock to the tank.
If you can't take the rock out stick very closely to the instructions of the product you want to use. Kalkpaste works as well and many people simply cover the spot in glue.

The "worm" looks like a potential nudibranch. These usually have very specific diets and don't survive in tanks for long if they aren't specialized on something that we have in our tanks (like corals). A tiny selection of them is beneficial like Berghia sp. that are specialized on Aiptasiidae so they can be effectively used against an infestation. However, some are more generally "corallivore" and start eating coral tissue.

I would wait until the lights are off for a while and then check all corals with a flashlight. Maybe you see any sort of parasites. You will certainly see copepods, isopods, and amphipods. Those are fine, most bristleworms will be fine as well, but if you see flatworms, or the nudibranch again, try to take it out.

 

[SeamusHarper]

I know I have a number of pods, I've seen them moving within the coral and I also have stomatellas.

I don't think I've seen flatworms yet but I'll keep an eye out for the worm I saw this morning.

Lights are off right now, I don't see anything although I'm seeing webbing on some corals and last night I saw a thick mucous wafting out of another coral.

I don't know what to do from here, I don't want to lose all the corals in my tank whilst having no idea what's going on

 

[Mr. Mojo Rising]

My jack o lantern occasionally gets little white spots, I don't know what they are but they usually heal within a day or two. Overall it looks rather fine to me.

But the first line of your post says many corals have died, what exactly died? Where is the picture of the torch? Can you post picture of other affected corals? Pictures of the webbing hanging off the corals? Can you post a full tank picture so we can see everything?

Can you tell us about your lighting and flow?