Puffer floating at the top of tank -help

[fishoholic]

Was up late last night trying to make a cave for him to hide in and I got him under a rock area but stressed him out in the process and he didn't stay under the rock cave for long. Debated shutting off the return pump but the heater is in the sump and no heat to the tank all night would drop the temp to low.

Sadly I found him dead stuck to the side of the overflow box this morning

I honestly thought he'd be ok, since he was so different from the other fish (and no one picks on the toby puffer in my fowlr tank), that no one would pick on him either. My mean trigger chased him once when he first went into the tank but then everyone seemed to be getting along fine. Watched the tank closely all day, and all seemed well, until around 11pm that my snowflake eel decided to try to eat him I banged on the glass distracting the eel away from him which seemed to work and he was ok for a little while but shortly after that I saw him puff up and it was all downhill from there I feel sick and horrible about the whole thing and feel like an idiot for thinking he'd be fine in my fowlr

RIP spike