Personally, I think if you can write five pages on whether or not to get a fish, then you probably should get the fish! In other words, give him a better home than what he has now. Even if he doesn't survive, at least you will have given him a chance at life, and that in itself is a blessing that only you can give him right now.
Yes, even if he doesn't make it, give him a nice home to pass in with love and clean water. Show him what plants are like, and stretching those fins. Let him know what swimming really is. Please, go back and get him :(
If you're worrying about him so much, then I would say go ahead and get him. The guy looks like he could use lots of love if he's to survive! If he is, in fact, terminal, then at least you tried rather than continuing in the endless cycle of "what if?"
That's true too. I know, he would have a better home and things but the reaction I'm getting towards him at home is exactly the opposite to here. :( My grandmum says no more fish for awhile, she's sick of looking at aquariums everywhere and my sister keeps saying that if I want a HM I should get a nice healthy one instead of this guy because they're expensive and I'd be wasting my money if he died. She also keeps scaring me with the fact that he might give my other boys something.. Basically everyone is against it. Only bf says I should get him if I it means so much to me and that I shouldn't listen to anyone else... But I don't have to live with him.. Sigh... I have to go pick him up in the evening if I do. I guess I'll decide at the last moment. I'll have to go against my grandmum's wishes but she wont notice him for atleast 3 days lol! Hopefully by then she would have forgotten what she said. (She usually does..)