So I got a gold maxima about 6 months ago it was pale yellowish then turned yellow with black markings then turned almost all black and now is changing to blue/purple???
I have never experienced this what's up???
My experience with small 1.5-2.5" Maxima's and Crocea
is that some are held in low light conditions and shipped rather carelessly over seas to distributors. Some loose a great deal of zooxanthella during there journey to our LFS and or our tanks. Usually the darker the color of the mantle, the healthier the clam. Also could be caused from a change in light spectrum not intensity. Like 10k - 20k or higher. As long as you don't see any tissue recession or whitening around the inhalant syphon or incurrent syphon it should be fine. Bonus for the purple color.
I've had them change colors dramatically as well, it seems to depend on PAR and spectrum. I wouldn't worry as long as it's growing. Like anything in the ocean, it's either growing or dying.