Hard to say what is wrong, but lower temps often lead to fish hanging at the bottom, fin clamped, and susceptible to ich. At least he's eating. I would rais the temp to about 80 F and provide hiding places (plants, shale, etc..)

IF i do raise the temperature will it affect the other fish i have in there such as a pleco, humbugs, guppies, tetras and clown loaches?

I'm not familiar with a humbug (it must have another name), but all the rest are tropicals and 80 isn't too warm for them. I would also make sure there is adequate aeration / filtration, as that also increases their metabolism.

they arent humbug fish- but we call them humbug catfish- their real name is Striped Raphael (Talking) Catfish ...
there is a constant air pump running and it only seems to be the 1 fish thats affected.