Gigas clam dead

my 12" gigas clam died literally overnight....need help as to what can cause it.
dead:


couple months ago:


Tank specs: 135g with 60g sump, koralia 8 and 4 internal pumps, 4 250W 14K MH, 8 actenic (bulbs under 6months), 2 UV sterilizers, skimmer, chiller, and run carbon and phosban. The tank is SPS/LPS with several clams. I only have 3 fish (female bellus, mystery wrasse and midas) Ammonia and nitrites zero, nitrates 20 (I know it is elevated but it has been fine), pH 8, kH 10-14, mg 13-1400, calcium 480.

All my other corals and clams are doing great. There are no pyramid snails or other pests....

Last night clam was open and doing great. Reactive, etc. This evening noticed was closing up and not looking good. A couple hours later it was the picture above.

So I figured I could let it die in my reef tank, or I could give my golden puffer an expensive treat...so Goldie is having a feast.

Any suggestions? Again, no pyramid snails..

 

Are you sure it is dead?

When I have clams die, they are picked totally clean by the CUC in a few hours.

 

Sorry for your loss, maybe it was just the clam's time if everything was going well.

 

that clam was pretty big, and just like all creatures, they die. many people think there always has to be a human error on the death of a critter but sometimes they just expired. sorry for your loss

 

In the wild, clams live to be very old. However, it is very possible that because of the closed environment, it was just his time.

 

thats weird, ive never really heard of a clam that big expire so fast. usually what i thought is the die a more slow death of starvation.

 

i would find it very hard to believe it starved in my tank...I have a sea apple and a psychedelic cucumber that I target feed and I target feed my tank at least 3 times a week with a combination of zooplankton, live phyto, coral amino, restor and coral freenzy. I turn off my pumps and use a baster and place this mixture on all my specific corals. I leave the pumps off for at least 15 minutes when I feed. I dont directly place the mixture on these clams (as they are all over 2") but I do place the mixture around the clam. On Monday when I fed the clam was very reactive.

I kid you not....it was fully opened, no pinched mantle nothing one day, sunken in the next day. Inwall saw it and can attest to it.....however we are both stumped.

I have wondered if maybe my bellus has decided to start eating it, however it wasnt withdrawn and I never see her by it.

The other possibility is I have a very big crab that I saw a week or so that I have never seen. I can not identify it and it has been popping off my trumpet tops.

There were some CUC on it when I got home last night. However in the morning it was fine, in the afternoon it looked poorly and I did not see anything on it and a couple hours later it was that picture.

 

Clams can take a yr to die and if anyone can not see this clam is toast then I'd suggest they never try clams again , Had you ever seen any signs of distress like pinched mantel or fading ? Have you ever dipped it in F/W to rid it of any parasites like pyramid snails or worms ? I would always dip and clam to keep the aquarium parasite free . Had you recently physically tried to relocate the clam to a digfferent spot ?

 

I've seen this clam many times. In fact, because this clam was fairly large, last week I was looking into it's incurrent siphon hoping to get a pic of a tridacnid commensal shrimp (if it had one). It's gills were fully inflated and looked healthy. There was no pinched mantle nor any pyramid snails. It would allow her bi-color blenny to rest on it's mantle but if any other fish came by, it was reactive and closed quickly. The clam hasn't been moved so it wasn't a byssal thread issue. I truly have never seen anything like it in my life. As stated earlier.....they die slowly over time. This T. gigas was putting down additional shell well. The water parameters are in line. This guy literally died in one day and nothing was changed in the tank.

 

I wonder if at 12", gigas clams still use byssal threads? Any idea at what size they rely on weight and size alone to keep them in place?