New Derasa and Possible Health Issue.

[Seanfg89]

I recently acquired a small (2.5 inch) Tridacna Derasa clam and currently have it in one of my 2.5g picos. Before I start getting lectured about the size they can reach I just want you to know I got it covered, I have a 55g (at least) in the works and should be up within a month or two and will move it to that later on down the road. Anyways when I got it, it looked very healthy with nice extension and quick reflexes with regards to light changes. When I first put it in it was closed for an hour or so but after that it opened up nicely and was happy as well...a clam. Today however, it's incurrent siphon is opened quite largely and I am afraid its not doing too well, I've heard this condition is called "gaping". It still has great extension of it's mantle and is very quick to react if there is a change in the light. I placed it in a nice open area of the sand where its pretty much by itself.

 

My parameters are as follows:

Salinity:1.0235

pH:8.2

Alk:4.1-4.3 mEq/L

Ammonia and Nitrites:0

Nitrates:<10

Calcium:450

Lighting:24w 50/50 + 18w Actinic

 

There are no parasites or any of those snails that eat Tridacnas and nothing in my tank that goes near it or bothers it. Everything else in this tank is flourishing, Pom Pom Crab, Zoanthids, Palythoas, Mushrooms, Ricordeas, Hermits, and Snails. I did do my 15% weekly change today with the replacement water matching the parameters of the tank water. I also have it in a very low flow part of the tank so that the flow does not move the mantle at all. Is it just still acclimating or am I missing something?

 

Included is a picture of it showing its extension and gaping siphon. The picture was taken without flash with all of the normal tank lights on but it still looks like it was taken under Actinics. I would appreciate any help and thank you in advance.

 

Edit: Sorry, I forgot to add that it does have full control of the muscle that controls that siphon and when the lights go out, it does snap it shut really quickly, its just when the lights are on and its extended during the day that its siphon gapes.

 

 

[cyenna]

I also have it in a very low flow part of the tank so that the flow does not move the mantle at all. Is it just still acclimating or am I missing something?

 

 

I don't know much about clams but I have found that my clam likes moderate flow. They are filter feeders after all.... I have a friend who has his maxima in super high flow and it's growing like crazy. I have mine in moderate flow and it has been steadily growing new scutes. Both our clams started out about 2 inches. He doesn't bother to feed any phyto, i only recently started feeding. Both our clams appear healthy. I don't know if gaping has anything to do with feeding but I thought I'd share. Hope you figure things out!

[Seanfg89]

Well actually the damnedest thing happened, as soon as I posted this question, he stopped gaping and now his incurrent siphon is an oval slit like it should be. Anyways, thanks for the information on flow, I've read conflicting reports that they should have light-moderate flow to feed but also that they like very little flow because higher flow can disturb their mantle. I'll play with the flow settings and see how he responds.

[this1fish]

well, i've never had much experience with them but, isn't your lighting alittle too low for it? i've read and was recommended that they will do best with metal halides and PC's aren't all that great for them.

[Seanfg89]

My research has led me to understand that Derasa, Squamosa, and Gigas can do very well under PC given that there is enough light with Derasa being the most forgiving when it comes to lighting. The store (crappy mall pet store) that I bought it from had Derasas and Croceas under 45w Normal Output Fluorescent and I watched them for a month to see if they were indeed healthy specimens. After a month I could clearly see new growth segments on the shells and that they had lost no color whatsoever so I'm guessing if 45w NO is good enough for even Croceas then 42CF should be good enough for a Derasa, also taking into consideration that the clam is now closer to my lights then it was at the store.

[this1fish]

My research has led me to understand that Derasa, Squamosa, and Gigas can do very well under PC given that there is enough light with Derasa being the most forgiving when it comes to lighting. The store (crappy mall pet store) that I bought it from had Derasas and Croceas under 45w Normal Output Fluorescent and I watched them for a month to see if they were indeed healthy specimens. After a month I could clearly see new growth segments on the shells and that they had lost no color whatsoever so I'm guessing if 45w NO is good enough for even Croceas then 42CF should be good enough for a Derasa, also taking into consideration that the clam is now closer to my lights then it was at the store.

 

 

if that is so, keep me updated, i've wanted a clam for the longest time now.