Derasa not opening

[TWallace]

I've had this derasa clam for about 8 months and it's always looked great until two days ago. It's only opening a little bit. I've checked it's foot area for pyramidellid snails and don't see anything. Recent changes to the tank include a neon goby, which LOVES the derasa. It rests on its shell and its mantle occasionally. The clam will sometimes snap shut, evicting the goby, but he comes back eventually. Are these fish known for being clam pests? The goby also likes to perch on a nearby Christmas tree worm rock, so he's not constantly on the clam. He probably spends about 20% of the time by the clam.

Also, I recently started adding Seachem Reef iodide to the tank last week. And finally someone gave me 5 trochus snails last weekend in exchange for some xenia.

Yesterday I noticed that my galaxea was sending out some really long sweeper tentacles, possibly stinging the clam. I moved the galaxea far away yesterday, but the clam still doesn't look any better. Perhaps it's a combination of goby and galaxea stings?

I've got 3 croceas in the same tank and all look great, full extension, no problems. In fact, every other living thing in the tank is looking good, too. So I'm pretty sure it's not a lighting or water quality issue.

 

[alan214]

I'd be most suspicious of the Goby harassing the clam.

 

[TWallace]

The clam is opened up more at night than it is in the day time, so I'm starting to agree that it is the neon goby causing this. This morning right after the lights came on, the clam looked great, then the goby woke up and start bothering it, and the clam closed up a bit. Does anyone have experience with a similar situation? Will my clam learn to deal with the fish, or will one or the other have to go?

 

[Loralie]

Lift the Derasa up and look along the seam. If you see small snails there, you have a problem. those are prymidal (spelling not correct) snails. They are common on Derasa clams and will kill them. they are cone shaped tiny white snails. Take the clam out and rinse the seam with RO water until snails are gone. Then keep an eye out for re infestations.

 

[Loralie]

I have a pair of Maroons ( the female is 5"+) that host my gigas. I have also seen clowns host derasa and crocea's as well.

 

[RichConley]

That fish almost looks like one of those red sea mimic cleaners that are obligate corralivores.


That being said, what is your Alk/Mag/Ca?

 

[Loralie]

I looked it up in the clam forum...it is pyramid snail. They have some pictures posted in there. There is a thread started on pyramid snails.

 

[TWallace]

When I came home tonight, the clam looked much better. At the same time, I couldn't find my neon goby. He remained hidden for about half an hour until I saw him. He seems to be leaving the clam alone now.