Hard to tell in the blues but yes it could be and if it is I’d remove , dip , and put in quarantine
Try dipping in iodine and raising the current in the quarantine tank . It’s not easy to cure but if you work quickly you might have a small chance . Only other thing is to try to frag any good parts of it . This will be very stressful on the coral . Get a positive diagnosis before taking the action stated above as the pic shown is too blue for me to tell and I’m not a expert on brown jelly as I’ve never experienced it before personally sure it’s not algae