Gigas...how do you tell if it is one

[B2]

Hello my Friends

First time to post in this column. How do you tell if the LFS that says they have a Gigas if it really is. I know I need to get a book on them.(knop) What is the shell structure different on them to others. The one the have looks like a dersea but has blue dots on it instead of blue-green lines. I do not trust local lfs around here so any help with out flame would be apprecited. I know in the future I will own a few clams but of course knowing me I have alot of info to gather and 3 months to contemplate it.

B2

 

[OrionN]

A derassa with blue spots would be a very rare find. From this alone I would consider they have a T. gigas. Search the old Aquarium Frontier Magazine. D. Knop had several articles on clams and one of ther article deals exclusivly on T. gigas.
With all that, T. gigas has smooth shell. As a baby, they can close their shell but as a older clam (4 inches or so) they cannot close their shell completly. Healthy T. gigas open their shell wider than T. derassa.
You can find a picture of a young T. gigas in the pictures of my tank (in Seattle) and can see the same T. gigas at about 16 inches in my current tank. Links to my two tanks is in my sig below. Look at the picture. Once you see a picture, it is very easy to tell them apart.
Be warn the T. gigas grow extreemly fast. Mine is about to out growth my 400 g tank.

 

[OrionN]

Baby T. gigas is seen here. The second picture. The clam next to the yellow tang, on the sand
http://berlinmethod.com/minhn/reef01.html
Older gigas can be seen here:
http://berlinmethod.com/minhn/T.gigas.JPG

 

[clamz]

basicaly the t. gigas has more pronounced vertical folds (teeth) near the upper rim. it is one way of telling gigas apart from t. derasa

 

[OrionN]

basicaly the t. gigas has more pronounced vertical folds (teeth) near the upper rim. it is one way of telling gigas apart from t. derasa

This is true for an older T. gigas. A small T. gigas harly have any teeht or fold at all, just like the T. derasa.

 

[B2]

thank you for all your replies