What is wrong with these montis?

Averhoeven · May 12, 2020

These 2 montis were starting to encroach on each other. Then all of a sudden yesterday the leading edges of them bleached out and have receded with this "brown jelly looking tissue" that's floating near the edge of the bleached portion. What is this? Is there a way to treat this in the tank because the rock they are on is pretty not movable. The red one is significantly more impacted, but the green is slowly receding as well. They were both growing phenomenally (too well) until this.

vetteguy53081 · May 12, 2020

Appears to be the result of:
High alk
High mag
High salinity

OR ALL OF THE ABOVE. Test and verify these readings as well as ph. These guys also love good flow.

Averhoeven · May 12, 2020

Salinity: 1.026 (refractometer)
Alk: 9.21 (Trident) usually maintain at 9,but did a water change yesterday afternoon (after I first noticed this starting)
Mg 1449 (Trident)
pH 8.43 (Apex probe)

bobby.w.hodges · May 12, 2020

Not all montipora play nicely with other montipora, that's why they're are only so many grated versions of Monti.

Reeffraff · May 12, 2020

bobby.w.hodges said:
Not all montipora play nicely with other montipora

This. I believe what you are seeing is result of coral warfare. Large sections of the 'losing' coral can be affected.

Averhoeven · May 12, 2020

Averhoeven said:
Salinity: 1.026 (refractometer)
Alk: 9.21 (Trident) usually maintain at 9,but did a water change yesterday afternoon (after I first noticed this starting)
Mg 1449 (Trident)
pH 8.43 (Apex probe)

Figured I would add my other parameters.
Nitrate: 12 (red sea)
Phos: 0.14 (Hannah)
Alk: 8.0 (Hannah) the trident and my Hannah have always disagreed by about this much even after I calibrated the trident. I figure as long as it's consistent, the exact numbers don't matter that much.

Also, these 2 are actually almost exactly opposite an MP40. They probably have some of the highest flow in the tank.

F i s h y · May 12, 2020

They are fighting. They don't like each other. Hopefully the damage doesn't kill the entire colonies.

homer1475 · May 13, 2020

Coral warfare. Competing for space. Either separate them, or one colony will win, killing the other off.

Averhoeven · May 13, 2020

So the option is frag and move I guess? Weird. They were getting along well for months.

Edit: When I went down this morning, the majority of the red one was gone. That was fast. I fragged the unaffected parts easily at least because it SAS essentially just the overhang. There has been a little further destruction of the green one. Since I crashed the fragged the red one, should I anticipate an end to the losses of the green one?

I have lots of montis in close proximity that have been for a long time like these 2 were. Should I worry that any of them could suddenly turn on its neighbors like this?