Quack just has all kinds of problems, @themanwithnoname. What's a duck to do when he's made of by his own kind and fish won't leave his tender feet alone? It's sad that he would go to the extreme of depressing fish or essentially drowning them with air.
Some days, it's not worth rolling out of the bush, or pile of hay, or wherever Quack sleeps, because you just know it's going to be lousy, so you might as well just stay there than get homicidal.
I think he was just feeling a little overwhelmed. It's tough when you can't get some peace and quiet. Even ducks need a break from it all sometimes. Yep, no one really saw Quack committing fishicide, but life can drive a duck to do terrible things.
Hopefully Quack will have a better day tomorrow. And then maybe all the fish won't have to die. Or maybe the fish could just be nicer.
I don't know how much Perry Mason you've watched over the years, but there always seemed to be shows where the otherwise nice person was driven to murder because of the actions of the truly evil character in the story.
While I don't condone murder, and obviously, it was still fiction, I've wondered just what I'm supposed to get out of any of that. Even bad, nasty, people don't deserve to die, or killing is never justified?
I would imagine, though, along with the actual killing, the other problem was, they were trying to get away with it, and usually letting someone be framed, if not purposefully doing it, so the act of murder was compounded with lies and so forth.
Now, we've got anti-heroes running around killing people left and right in our movies and television shows, and all of its somehow justified.