Montipora disease?

ThePurple12 · Dec 27, 2019

The flesh of my two purple montiporas (ID?) have been eroding very slowly for months.

What's going on? Both corals were doing fine before. The bare patches have been slowly spreading for months now. My other montis (mystic sunset and 3 capricornis) are fine. I haven't seen any eggs or bugs or anything on them.

The top picture shows what the bigger coral used to look like, and the bottom two show what both look like now.

Edit: The little purple spikes are where the corals grew over vermetid snails.

Before:

After (bottom left)

The other one:

ndrwater · Dec 27, 2019

The sunset looks like it is over running the purple. Sunset can be very agressive.
Remember corals dont have teeth or claws, so they fight chemical warfare. Usually leading with a toxic (and usually invisible to us) front line before following up with new growth

jda · Dec 27, 2019

That is textbook STN - slow tissue necrosis.

Standard causes include, improper lighting, improper flow, parameters out of whack, parameters that swing too much, heavy metals in the water, stray current and nippers or pests.

Most are going to want a gamut of equipment or parameters to try and help. Just know that everybody is going to flock to low N and P if they think that you are too low by their own standards, but if the other stuff is growing well, or if you have algae in the tank or on the glass, then this is not your issue.

ThePurple12 · Dec 27, 2019

jda said:
That is textbook STN - slow tissue necrosis.

Standard causes include, improper lighting, improper flow, parameters out of whack, parameters that swing too much, heavy metals in the water, stray current and nippers or pests.

Most are going to want a gamut of equipment or parameters to try and help. Just know that everybody is going to flock to low N and P if they think that you are too low by their own standards, but if the other stuff is growing well, or if you have algae in the tank or on the glass, then this is not your issue.

Thanks, what should I do? The smaller one is close to the light with more flow, while the bigger one is near the sand with not as much flow. My parameters are pretty stable, so it seems like it's some kind of pest that only affects that species. Can I dip in hydrogen peroxide?