A true Mega fish, will all in when they have a hand, they don't understand the concept of betting for value. Most mega-fishes employ this tactic, which makes me deathly fearful of their all in bets, and they are more often a made hand than a bluff,

I think you underbet the flop and it may have cost you, I put our fish on A-5 considering he probably also drastically overvalues A-x, I would have to fold this hand, and I be pissed at myself for my bet on the flop