Green hairy mushroom splitting?

[Ioncewaslegend]

So I noticed a couple days ago my GHM looked like its mouth was opening. I kept an eye on it, and it didn't really extend yesterday, but the opening got even bigger (and has even exposed what I assume was the original plug underneath). Picture was taken at night after everything had receded; the other GHM on the right has seemed okay (though it's never been as bright green as the other one).

Any thoughts? Ammonia, nitrite, nitrate, and phosphate are all at 0 (working on getting that up since I'm battling GHA), and there's been no temp/pH/salinity swings.

 

[Webslinger]

or dying,time will tell.