monti has spots, what could be the culprit?

[Ennvi]

i know they get white when they grow, but i thought that was just at the edges. what could this be?
I'll test parameters tomorrow, just wanted to get this out there for opinions!

 

[Alexopora]

i know they get white when they grow, but i thought that was just at the edges. what could this be?
I'll test parameters tomorrow, just wanted to get this out there for opinions!

Besides less than favourable parameters, I’d say probably coral aggression or pests. If you happen to have an lps or sps with sweepers(leptoseris, pavona etc), check and observe after the lights out if they extend sweepers that might come in contact with the monti. Besides coral aggression, I’d say pests could be a probability. Since its mostly the edges where the flesh are receding or disappearing, i can only think of either Monti Eating Nudis or digitate hydroids. To look for either one, observe after the lights are out. Monti Eating Nudis generally would hide on the shaded parts of the monti while digitate hydroids could be on the sand or nearby rocks. Digitate hydroids look like whips with a feathery bulb on its end.