I woke up early this morning and my light turned on revealing my single clownfish it’s head is pale and it’s swimming along the top of the tank sometimes on it’s side. this is my first fish and im not sure what to do. everything else seems fine. i did a water change yesterday. the only thing that happened that wa about do the ordinary was me putting a bag of activated carbon that hadn’t been washed in the filter, it fizzled up for a second then i took it out, i did t put it back in. help