Sorry to hear that Spence, I just lost a lemon yellow cichlid and her brood to lockjaw. From what I could find out about it, there seemed to be no reason and no "cure". If the Midas cannot properly function its mouth, not enough oxygenated water will flow over the gills causing the fish to suffocate. I'm sorry I cannot be of more help, but when I posted "Death of Lemon Yellow Cichlid and Brood due to Lockjaw (?)" last month, no one had any answers.
I wish you the best of luck with your Midas and if you fix the problem, let us know.