Where did my fish go??

i have a normal size fish tank (no idea how many gallons). i used to hav two ciclids. one male (blue) one female (yellow), and two upside down catfish. the problem is that since two weeks ago the blue ciclid just dissapeared. i checked inside every ornament and filter. he's not there. is it possible, that one of the catfish might have eaten him, since he's looking alot bogger these days?