This thread is hijacked....for the time being
I dont know if you should suspect the shark in the neon deaths
I know I had 10+neons, and one by one they got "abducted".
Now, I have nothing predatory, however, I did have one big pleco that hoovered anything on the tank bottom, dead fish and all.
So, with that in mind, I wouldnt doubt if your shark munched away, however, it could also be that they choked and your pleco had a mini feast.