I am glad that the fish has eaten and that problems may be partly resolved. Stray voltage may have something to do but other factors almost certainly do as well.
You have been given good advice.
For the long term (as in these fish can live many years!), you should consider some important changes in maintenance:
As mentioned here
It could be the high nitrates, not sure if they are super sensitive fish but nitrates can slowly harm the fish over time so a 50% water change and test again. See what it is at and if it still a bit high you could do another 25% water change the next day.
Your nitrate level is high. 40ppm is high no matter what, and if chronically so, it is damaging to most fish. The damage is not acute (effects seen mostly eventually, not immediately). 40-50% water change monthly is woefully low (although there are different schools of thought on this), particularly with a fish of that size in a 100g tank. Perhaps less water changes were sufficient when the fish was smaller, but not now. Nitrate level attest to that.
One should always strive for the lowest nitrate level possible, even though for some of us, the tap water already contains detectable amounts of nitrate. 20ppm is better (but not ideal long-term) and if one can lower it via water changes, one should.
I do ~70% water changes weekly in each of my aquariums, all of which are also fairly heavily planted (so plants take some nitrate as well). I wish I could do even more. I suggest you need at least that, and nitrate level should stay lower.
Your fish is beautiful! Good luck!
