I have a 2 year old midas cichlid in 75 gallon tank. 2 fluval 306 canister filters. He has been fine up until 3 weeks ago. He became agitated as if he was stressed out or angry. Everytime i walked into the room he would face the wall away from me as if he was pissed off. Now, he comes to the front of tank like he wants to he, i drop a pellet and he eats it and spits it out. Water is fine. He only like pellet food but wont eat it. And he is obsessed with the gravel. Moves it all day long into piles. Any advice would be great.