why are my maximas so different

[whatcaneyedo]

I have these two clams (and 4 others.... lol) The blue one was given to me 2 years ago and came from a small nano tank with PC lighting and fluctuating water perameters. The gold tear drop one I bought last christmas. Both sit in the same place in the sand with rocks undernearth and 250W 13K MH above. The gold one had put on some nice big growths of shell in the last year and opens fully all the time. While the blue one bairly grows or opens and has been that way since the day I got it 2 years ago. Here are two picture I have, the one that shows 4 clams (my crocea and squamosa as well) is from last year and the one that shows two is recent.

 

[a4twenty]

because the blue on is a crocea ( does he have a smooth shell? ) and they are the smallest and slowest growing of the tridacnids.

 

[whatcaneyedo]

In the top picture, left to right its suppose to be maxima, crocea, maxima, squamosa... but I think you're right. The shell on the top "maxima/crocea" is rather smooth except for some of the new growth and now that I look closer that does seem to be very similar to the clam that I know is a crocea. I feel silly. Lets all just pretend like I didnt post this.

 

[unbreakable]

the two blues look like croceas, the one next to the squamosa is a maxima

 

[whatcaneyedo]

I was told it was a maxima when it was given to me and I never questioned that until now but I guess I was mistaken all along. I moved the clam up into a higher area in the tank just now so that should make it happier. Now both of my croceas are in the rocks and the maxima, squamosa and two derasas are in the sand bed.

Heres my derasas when I got them back in September. Both have colored up a lot more and put on a 1/4 inch of new growth since then. I'd post a new pic but my camera died on me...

 

[a4twenty]

the crocea is also known as a boring clam because it can bore into limestone and coral skeletons. when in does this it loses it scutes ( they get ground off ) but it is quite common for the scutes to reappear on new growth in an aquarium.

you got some sweet clams there