Unfortunately, I have sad news to report. For some unknown reason, my gig began contracting. Note, I didn't say deflate -- it would try to squeeze its body into a compressed form, but its tentacles were still inflated. Upon closer inspection, I noticed that a portion of the body had necrotic tissue:
I quickly removed the gig to a QT tank and began treating with Cipro. Unfortunately, I knew that Cipro probably couldn't help because a portion of the nem was already dead (this did not appear to be a typical internal bacterial infection where the nem deflates). I've had nems (even a gig) get chewed up by powerheads, and all survived. But this was different because it wasn't torn flesh, it was dead flesh.
Upon closer inspection of the underside of the oral disc, I noticed that the damage was where the cut once was:
If you look carefully, you can see verrucae around the entire disc. The scar tissue didn't have any verrucae, which is why I believe the damage was at the cut site. I can only assume the cut site had something to do with the death of the nem. However, I've had the gig for over 10 months. Once I knew the nem was able to eat, I was feeding it heavily and it more than doubled in size. My only hypothesis (aside from it being attacked by a predator, which I highly doubt as my breeding pair of clowns don't let anything near the nem) is that this feeding may have been too much for the nem to deal with, especially since it may have only half of the required body parts.
My postmortem analysis revealed that it only had only siphonoglyph. I opened the mouth to look for the second set of "buck teeth" (gigs typically have a pair, one on each opposite end of the mouth), but I could not fine one. This leads me to believe that my "one lung" theory holds true -- that it was half a nem that was able to heal itself.
What's odd is that the nem was showing all the signs of a healthy gig. Until a few days ago. If anything, it just goes to show that cut gigs DO NOT survive for the long term.