Im not getting any growth out of my crocea

[FindingSalt]

Its been about a year and my clam is still about the same size. I mean whats the growth rate on the crocea are they slow growers?? I have a 30 gallon tank with a 250 watt 10 k bulb and 2 96 watt actinics on it. Any thoughts????

 

[ChickenCannoneer]

check your calcium and alk levels. if they are low then you will not get any growth. also check when it is closed up if there is any white line across the top of the shell this is what new growth would look like.

 

[kfisc]

They tend to reach 9" or so at best- I've never seen/heard of a captive specimen beyond 6". It may be done. They're also fairly slow growers.

 

[critterkeeper]

Largest crocea in the scientific literature is only 6" (15cm). I saw an aquarium specimen in a book that was supposedly bigger, but I wonder if they actually took it out and measured it correctly - or just eyeballed it...

Even in their natural habitat under full sun, croceas may grow less than 1mm per month. They are by far the slowest growing of the species. Still, I'd think you should see at least a little growth in a year's time though. As already said, it could very well be too little Ca/Alk, but too much phosphate can also interfere with shell formation, too.

 

[Opcn]

Croceas are indeed the slowest growing giant clam, however there are specemins larger than 6" on recors, I measured on that was 7 and a quarter at my LFS, I used calipers.