Temperature drop, ram cichlid isn't doing well

[Madi157]

I've had my tank up and running for a year and a half, I've had my blue ram cichlid for a year, he was just a little guy when I got him and he has done very well, 2 days ago the heater to my tank stopped working so the temperature dropped from a consistent 78 down to 70, I immediately bought a new heater and with in a few hours the temperature was back up, all the other fish are doing fine and are back to normal but my blue ram cichlid has not recovered, he is very dark, he isn't eating, and he just hangs down at the bottom of the tank no swimming around. I really don't want to lose him, what could be wrong and is it possible he could snap put of this and get better? Thank you for any help!