Redhead Solon fairy wrasse laying at bottom of tank

I have a redhead Solon fairy wrasse that has been mostly laying on its side and sometimes back on the bottom of my tank the past two days. It will eat if you put food in front of it and will swim around a little bit like everything is normal. He breathes hard and looks around like he is dying but then acts fine and back to lying on side. Anyone know what could be wrong? He's been fine the past two months I've had him and I've changed nothing.