Crocea dying - cause?

[MrMreef]

Hey Guys,

My crocea has been going strong for 4 months now and tank params have been pretty stable since Christmas (dKH 8.5, temp 78/25.9, sal 35.4 ppm, Ca 430, Mg 1350, NO3 low at 0-5ppm, PO4 at 0.03). No ICP detectable nasties and I run carbon and dose phyto regularly.

Her spot gets about 150 PAR peak with a slow ramp up from blues to a white mix for 4 hours. Previously she had huge mantle extension and signs of significant growth.

A few days ago I did my morning check and found her on the sand next to her place on the rocks, so I propped her back in her place. That day - and the day after - she didn’t extend as much, which I figured was due to stress.

Yesterday evening a few hours after a water change I checked up and she was on the sand again. As I picked her up I noticed the stone attached to her byssal gland was pretty loose and there was a black mass underneath (also attached to her foot). No sign of any gaping so I assumed that she’d be OK.

This morning I came to check on her and she’s not looking good - completely gaping and I think she’s passed.

What could have happened?

About 3 weeks ago I put in a Bella Goby that scatters sand everywhere - could this have irritated her to death?

Before and after pics attached… Thanks for the advice guys.

 

[Pkunk35]

Did you check for pyramillid snails? Check your turbo and other snail shells bottoms, see if you see them. I lost three crocea this way, the clams came in clean but my snails were already infested with them (obv unknowingly). Took months but eventually the little parasites found and killed my clams despite my cleaning and eliminating all regular snails. I would check for these before proceeding with any more clams, I feel as if only one can kill a clam if it gets inside.

 

[periocillin]

plantemita ?

 

[MrMreef]

Did you check for pyramillid snails? Check your turbo and other snail shells bottoms, see if you see them. I lost three crocea this way, the clams came in clean but my snails were already infested with them (obv unknowingly). Took months but eventually the little parasites found and killed my clams despite my cleaning and eliminating all regular snails. I would check for these before proceeding with any more clams, I feel as if only one can kill a clam if it gets inside.

Will check that out, haven’t pulled her from the tank yet…

 

[MrMreef]

plantemita ?

What’s that? A quick Google didn’t find anything like that

 

[JGT]

Good chance the goby was the cause. Did you notice sand on the clam? I have a Bella and while they are great at keeping the sand clean, they are a PITA as far as spreading sand all over bottom corals. I have an elegance that got sand dropped on it and tore up its flesh. Pulled it and put it in my hospital tank where it is looking like it will recover but no more Bella’s for me.

 

[MrMreef]

Good chance the goby was the cause. Did you notice sand on the clam? I have a Bella and while they are great at keeping the sand clean, they are a PITA as far as spreading sand all over bottom corals. I have an elegance that got sand dropped on it and tore up its flesh. Pulled it and put it in my hospital tank where it is looking like it will recover but no more Bella’s for me.

There was definitely sand on and also around the interior mantle of the clam - maybe it tore its foot trying to expel this?

 

[JGT]

There was definitely sand on and also around the interior mantle of the clam - maybe it tore its foot trying to expel this?

Or even the mantle itself.

 

[periocillin]

What’s that? A quick Google didn’t find anything like that

platelminta eat tridancna and bivalves

 

[periocillin]

What’s that? A quick Google didn’t find anything like that

platelminta eat tridancna and bivalves

 

[minus9]

It’s hard to say, but if had to guess, your clam was slowly starving. 150 micro moles is not much at all, especially with crocea. Your last pic shows the mantle fluted upwards and wide, trying to catch as much light as it can. It kinda looks a little bleached to me, but that could just be the angle? It’s also hard to tell from your pics, but there could be some pyramids on the shell or it could be sand? Regardless, croceas are the most light demanding clams and require a lot of it. In fact, I think it’s safe to say that it’s near impossible to provide too much light for croceas. If you’re not giving it 400+ micro moles, then you’re going to have problems long term.
Btw, sorry to hear about your clam.
If you’re serious about clams, then pick up James Fatherree’s latest book on Amazon. It’s the best $40 you can spend.