Nice stuff. I'd keep any eye on your crocea clam, it's pretty brown, and in the second to last picture, it doesn't look like it's growing (there's no white shell at the rim, which is the new growth). The derasa next to it looks like it is growing, at least it looks like there's some white shell along the rim. If clams aren't growing, it's a bad sign. What kind of lighting do you have?