Tank Wipe:(

[Oxymoron]

So I left for town for work for 3 days and come home to a rotting mess.
My 50 gal predator tank has suffered a complete wipe except for a peppermint shrimp and a snowflake moray.
It used to house a 2" koran Angel and a 2" valentini puffer as well as a 2" hawkfish.
Everything was fine. I left specific feeding instructions.
Apparently my puffer died last night and instead of telling me he decided to just toss him out and go ahead with his day.
I arrived today to see the hawkfish dead cloudy water and my eel breathing heavy.
After searching for the angel I found a third of his rotted body and Imagine he had died a couple days ago and was left to rot.
I've thrown the eel in the sump of my 90 gal and am hoping he will pull through.
Not sure where to go from here. Just thought I would share an experience I was hoping would never happen.
Im pretty upset with the whole situation at the moment and don't know what to do with this tank.
Any suggestions would be appreciated.