I'm sorry 4 ur loss. Tho his health wasn't perfect, Neptune lived a happy life, and u shouldn't b so hard on yourself... U did everything u could 4 him, so u didn't "fail" him. Neptune knows u love him, and he's at peace & no longer in pain from that nasty case of fin rot. Just know this.... He's swimming gracefully beneath the Rainbow bridge, his fins flowing & healthy again. I'm sure my boy Poisson has already met him at the entrance 2 guide him to his eternal home. I know it's hard, losing a beloved pet, but they answered the higher call 2 eternity, and will love on in our hearts. I still think of Poisson every day, but I know his soul has healed & the suffering is long past. It will b ok.... Hang in there. And the fountain by his tree is a great idea... And I'm sure will bring his spirit close when u miss him.