Please help me! My angelfish is dying!

I used to be a member here but lost my old user name password and frankly didn't have the time to bother looking for them because of this sudden emergency.......I'm soo distraught I don't know what to do! I have two adult angelfish that I have had for about two and a half years now. One of them, named "monster" is very sick and dying right now before my eyes! I am so attacehd to these fish I don't know what I will do!!! He seems to be having a lot of problems breathing and when I had the filter running he was swirling around in the current, he isn't swimming very well, not moving much, and even was floating around on his sides, not straight up like he is supposed to swim. I turned off the filter and put in some melafix...I'm sure that won't do much.....but if anybody knows ANY WAY I can save monster.....I will be eternally in your debt.......I just caught this about 5 minutes ago, yesterday monster seemed fine. I'm willing to do anything to try to save him.... I have never been so distraught over a fish before but I am SO attached to my angels I'm in tears right now please please someone.........

Thank you for replying Diana. I don't have a tank to move him into just the one 29 gallon tank with my other fish. There are two pictus catfish and one other angelfish in there. No new additions, no temp change or change of diet. Yes I don't think its old age either.

He does have some brownish/golden spots on his back, like near his fin...they seem to be part of his natural color but they are more predominant than they used to be. The other angelfish has the same coloring except its on his fin instead of his body and he is healthy. I couldn't really say if that goldish spotting is new or has always been there... it appears to be normal.

Could this be some kind of internal thing, like with the swim bladder? Since he can't swim well...? Or do you think those spots are something bad?


All of the fish are peaceful and don't bother eachother. But if I need to remove him I can put him in some sort of temporary container. Please let me know what you guys think.

Oh I can take a pic of the spots I'm talking about if that might help!!

Thank you both for your advice.....unfortunatley my fish died today. I am sad but I have realized I need to spend more time making sure my fishy friends are healthy so this won't happen again.