Sorry to hear about your fish.
I think my little endler is gone as well! I had just removed the guppie that had been terrorizing him the past 4 months, but in the process I may have terrorized the endler even more. He was still for about a day, with little swimming...and now I have no idea where he is. He had a gorgeous stripe...I hope at least he makes good food for the shrimp in the tank. I decided to finally remove the guppie when I saw it with a fairly large RCS in its mouth!