My purple hammer has done very well since the day I got him but the last week two of its heads have started to bleach. I don't know why. Everything else in the tank is doing well and is growing. Have another green hammer that looks amazing. Here is a picture from today.

Anyone have any ideas on what is going on and what to do in order to save the bleached heads?

Anyone have any ideas on what is going on and what to do in order to save the bleached heads?