Had to let go of a friend yesterday.

I feel your pain, man. We just had to put down our 17-year-old cat Biggie on Wednesday. His lungs were surrounded by fluid. :( My wife and I got him just before we got married, and we're both taking it pretty hard. He was a good boy. Here's a picture of him wearing a lei for some reason. :) Sorry for your loss...it stinks, I know.

My first cat I had as a kid ended up with a lung fluid and heart fluid issue.
I LOVED that cat. 20 plus pound street bruiser that frequently kicked dogs and raccoons ***', but was as gentle as could be with me. Smart as hell, too.

Vet said nothing to do, but he'd probably pass without pain.
We took him home and he made it another year. I believe he was only 8 or 9.