The gold foil maxima clam is a particulalry unique mutation we’ve seen only once before in giant clams. The unusual Tridacna maxima clam from ReefKoi has the pattern of an average high quality blue maxima, but the normally all blue coloration is overlaid in some parts of the mantle by a very different metallic gold foil coloration. The metallic gold region of the clam has a prismatic and opalescent effect in that it changes color like a prism, appearing most ‘reflective’ when viewed from above.
When looking at the image at left taken from the side of the aquarium, the gold foil maxima’s color appears splotchy blue and gold. However in the image above, taken with flash by James Fatheree, you can see how this metallic gold area looks when it is a little more directly illuminated.
Attendees of the last IMAC conference may recall a similar specimen of Tridacna crocea which has an identical appearance over part of its mantle: mostly blue with isolated patches of metallic gold areas. The gold and lustrous mutation is still unexplained and although we’ve seen it before, it was only once and that was almost five years ago. What is particulalry noteworthy is that now the splotchy metallic gold pattern has been documented in at least two species of Tridacna clams, so whatever causes the color change, it doesn’t appear to be species-specific.