Large Tridacna Clam I'd - I'm Stumped

It appears to be bleached and doesn't show any new shell growth ether.

Aha! Here's the guy I wanted to see here. Good point, I didn't even think about the lack of shell growth, or the bleaching in the mid section of the clam... but I'm sure Bongo Shrimp will get it resuscitated. :)
 
It appears to be bleached and doesn't show any new shell growth ether.

I don't have any experience with gigas but I feel like portions of lighter mantle are not uncommon. However, I've owned 2 dreasa clams that both got to about the same size as this clam. Each took about 7 years in my care to get to that size. Both had their shell growth slow at this size/age and both had their health decline (mantle retraction) and within a few months died. There were other tridacna species and individuals as well as many sensitive corals in the tank at the time that were uneffected. My hypothesis is that 7 years/8-10" shell length is the captive lifespan for derasa clams (at least under my care). Hopefully, this clam's fate is not the same.

Tom
 
It appears to be bleached and doesn't show any new shell growth ether.

Yeah I just got it three days ago from someone who had a fish start nipping it and had it under some rather low end LEDs. After a little tlc it'll be back to health. I now have him under a 6 bulb 36" T5 fixture and have been giving him some phyto daily.
 
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Also the reason you see all the slime all over him in the first pic is cause it was the day I got him and he was settling in.
 
I agree with derasa.

I've owned 2 dreasa clams that both got to about the same size as this clam. Each took about 7 years in my care to get to that size. Both had their shell growth slow at this size/age and both had their health decline (mantle retraction) and within a few months died. There were other tridacna species and individuals as well as many sensitive corals in the tank at the time that were uneffected. My hypothesis is that 7 years/8-10" shell length is the captive lifespan for derasa clams (at least under my care). Hopefully, this clam's fate is not the same.

Tom

Interesting. Mine just died for no apparent reason. 6 years in my tank and was about 9 inches. It started spawning one day and slowly withered away after that.
 
A unhealthy Derasa would be my guess too. FYI I had a 10" guy that grew like crazy right after spawning, like 1" of thin new material, then curled up and died. 7 years old.
 
Ok so hopefully in a month or so when he recovers the colors and pattern will help better identify him. Just so everyone knows I'm not here just to get a certain answer I want. No matter what he is I still like him and I knew he wasn't 100% when I got him. Guess I should have noted that in the original post.
 
Oh I would love to have him, no doubt about that!!
 
Looks like gigas x derasa or gigas x maxima to me. Unhealthy tho. Give him phyto and an Essential Elements dose and under propr lighting hopefully he will come back for you. Good luck!
 
Yeah I just got it three days ago from someone who had a fish start nipping it and had it under some rather low end LEDs. After a little tlc it'll be back to health. I now have him under a 6 bulb 36" T5 fixture and have been giving him some phyto daily.
^^^

Looks like gigas x derasa or gigas x maxima to me. Unhealthy tho. Give him phyto and an Essential Elements dose and under propr lighting hopefully he will come back for you. Good luck!
 
Here is a pic of the largest Derasa I ever had. Looks very similar to me.

DSCN2113.jpg


And here is a pic of the Giga's that I had, I sold it because it grew 5" in one year... Scared me LOL

IMG_0777.jpg


IMHO Bongo's clam is 100% Derasa, I still to this day do not believe there are cross bred clams...
 
Looks like a gigas to me
 
Definitely Derasa, if your lucky as it grows you may get the cool electric blue lines. It is common in the blue dot derasas as they grow, yet it is very rare to find a blue dot derasa collected.
 
Well he definitely is a derasa or has derasa in him. I've been doing some more research about it and I have seen similar morphs. I have found no scientific articles about definitive hybridization of tridacna clams although at least one mentioned that it may be possible. I also understand skinz opinion about the possibility that there might not be hybridization at all. Having read several articles that do suggest that hybridization is possible, I'm going to remain open to the fact that it may or may not be possible. In terms of this specific clam, he is gaining color back quickly and now has clearly visible, short, brown stripes that the more common dress have. Also, the more the "holes" color up the more we will be able to see if they are similar to those of T. gigas but for now they do not. The only thing that leaves me wondering, is how do we know that the morph with the holes is not a hybrid? We really couldn't know without some sort of DNA testing and comparison with known derasa and known gigas. I will see about a new picture to show how he is recovering.

reefsponge- during my own research I found a few other photos of a morph exactly like the one you posted. I am certain that the clam I have is the same morph, I'm just not convinced either way as to what it really is.
 
Well with the new maxima species they keep differentiating who is to say "different" looking clams from other non-maxima species, such as this one, won't be slid into new species categories eventually too.
 
Well with the new maxima species they keep differentiating who is to say "different" looking clams from other non-maxima species, such as this one, won't be slid into new species categories eventually too.

Exactly. Now I'm not saying I think this is a new species and I also understand how there are regional morphs as with some fish. I'm just saying it's really hard to get a definitive answer to this.
 

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