Gone Clam Crazy

[Crazy fishes]

Alright the title tells you a lot and I am just so fascinated by tridacna clams that I had to go out today and see if I could find any. As many of you may know I have already acquired a deresa clam which is really, really healthy (touch wood it stays that way). I have found loads of articles on them, some of which are very interesting and I will leave the web address at the end of this entry. Anyway I did find some but unfortunately the clam was not for sale due to it being firmly stuck to the rock work. A little way down the road and I found three which were all for sale!! Yippee heaven. Then came the difficult task of choosing one so I didn't I bought two instead!! I had a choice of a deresa, a maxima and another which I am having difficulty identifying. So I got a deal on two for £95, the maxima and the unidentified clam, which isn't a brilliant deal but better than nothing. After a little repositioning in the tank of rock work and corals they are finally in their new home and they look great.
Now I have posted some pictures: picture 1 unidentified clam, picture 2 maxima clam and picture 3 deresa clam (note the white area under the mantle that is new growth and why I say the clam is really really healthy). Regarding picture 1, I am caught between a T. maxima and T. gigas; the colouration looks like T. gigas (although rarely maxima can have gold colouration pastel greens) but the shape and prominent scutes are very much like T. maxima. Also before I forget the article is here: [URL="http/www.advancedaquarist.com/2009/3/aafeature1"]http/www.advancedaquarist.com/2009/3/aafeature1[/URL]
It is regarding so called mysterious deaths of tridacna clams, enjoy!!

 

[kj23502]

Cool. Glad you found some. It's disappointing when you go to look for something and can't find it.

Wonderful pictures

 

[Crazy fishes]

Thanks KJ, any ideas on the identified clam?? I would really like to know what it is because of positioning. At present it is about one and half to two feet directly below the halide (and that is about 10-12 inches from the water surface). If it is T. maxima it will probably have to be moved up in the tank or it will surely starve, slowly of course .

Regards

 

[jennybugs]

Very nice! I love clams too but my tank's not suitable

 

[Crazy fishes]

Thanks Jennybugs most appreciated. Is it the lighting they require so much!!

Anyone have ideas on the species of the clam in picture 1??? Please!!!

Regards

 

[SkiFletch]

Tridacna Squamosa judging by the color and shell pattern. MIGHT be a Gigas, but they usually don't have quite the shell ridges that one does.

 

[Crazy fishes]

Tridacna Squamosa judging by the color and shell pattern. MIGHT be a Gigas, but they usually don't have quite the shell ridges that one does.

Thanks ski, a squamosa eh? well should be ok where he is then. I think it is spinning itself on the spot to get the right amount of flow. I have some really sad news but not completely unexpected the maixima looks like it is dying !! It is a really tiny specimen about an inch long so they have a high death rate. I am curious as to what it disliked?? The water quality is good, lighting is strong (14 inches from a 150W halide, 6-8 inches from the water surface) and it can't be it has starved because it looked in really good health two days a go when I bought it. It was responding to shadows briskly and opening well with mantle fully extended. Now it is gaping with the mantle all shrivelled; this isn't a lighting issue this time. It has been disturbed quite a bit by crabs and urchins knocking it as they pass by possible this could be it.

Anyway thanks again for the ID most helpful

Regards

 

[ben1987]

nice additions, i love clams.

 

[SkiFletch]

While 14" under a 150watt halide is a lot CF, baby tridacnid clams have highly undeveloped vascular systems and thus have a much lower capacity for photosynthesis than their elders. All Tridacnid clams sold in the hobby are actually bred and aquacultured, they are NOT taken from captivity for collection concerns. I've you've ever seen the SE asian grow facilities, you'd understand how much light they need. These places grow the baby clams in full sunlight in mere inches of water. Your halide at that depth probably puts out ~100-150PAR, I know that noonday sun up here in the north pegs my PAR meter at 10,000... I can only imagine how much light energy must come at equatorial regions mere inches below the water.

FWIW the only folks in my local club that I know of who have been able to keep alive baby Tridacnids the size you describe either employed 250 watt halides with multiple T5 supplimental lamps directly under the surface, OR simply used 400 watters... Never heard of success with 150 or 175 watt halides.

 

[1234-fishy-freind]

Ski, would say 3 150watt halides be enough for a larger tridacnid clam then, one of about 6inches?


Josh

 

[Crazy fishes]

Thanks Ski, I was aware of the immature vasculature so was dosing phyto, but it didn't work. It is such a shame though; only two days and it perished. The shop I bought it from had it for several weeks under 3x 250W about 3-3.5 feet for the halide and at the far end of the tank (no cross over from the light cones).
The squamosa is going ok, but I think my urchin is trying to eat its shell!! I am moving the urchin to my other tank so I don't lose this one as well. Incidently T. squamosa has lighting requirements similiar to T. deresa, right?

Regards

 

[Crazy fishes]

Josh, if you are thinking of getting a Tridacna clam go for a T. Deresa. I have had one for several months and it is under a single 150 W halide and is really doing well. Look at the photos at the top, it is in the second and third. Unless you can get a 4 inch T. maxima I remember from previous discussions (and experience ) the death toll is high.

Regards

 

[SkiFletch]

Yup, agreed, Derasa and Squamosa need the least light, Crocea, Gigas, and especially Maxima needing the most light.

Josh, if you could find a clam with at least a 4" shell length like CF said, you should be fine. Remember, the low light guys can do OK in the sand, and the high light ones actually prefer to anchor into rocks, not sand

 

[1234-fishy-freind]

Ok thanks guys, T.Derasa it is.

By the way, sorry about stealing your thread Crazy fishes

Josh

 

[Crazy fishes]

Hey Josh you're not at all 'stealing the thread'; it is a forum to learn. I opened this post because it is an interesting topic which is key to my aquarium at the moment. If you need to know something relating to clams then this is the place to do it. I have some knowledge of clams which I am happy to share and Ski has his extensive knowledge bank so we can all help each other. I hope you find a T. deresa although the colours aren't as striking as T. maxima or T. crocea they are an exquisite species to keep. T. deresa generally has linear pattern (i.e a series of near on parallel lines). Also look from above the clam if you want to know its 'real' colours as when viewed from above it can be very different to the colours when viewed from the front of the tank. For incident my deresa has purple lines when viewed from the front of the tank but from above it becomes apparent that it is orange. This is an issue which can cause some confusion when identifying tridacna clams.
Just a few points when purchasing clams may be helpful:
1)Size, look at the size as is mentioned above 4 inches is a good cut off.
2)Is the clam open with the mantle (the coloured tissue used by the clam to photosynthesize) fully expanded? Does it hide the top rim of the shell?
3)Is the mantle colouration solid? No bleaching or pale areas?
4)Shadow test: place your hand over the clam to cast a shadow? How did the clam respond? Clams in good health will briskly respond with a slight to complete retraction of the mantle and closure of the shell. Clams, which are on the downward slope, respond sluggishly.
5)Ask to see the bottom of the clam. This has two functions firstly it lets you know the clam was not fixed to the substance. Some LFS owners/workers forcefully remove the clam which damages the foot and spells almost certain death for the clam. Secondly look for tiny snails a few mm in length around the hinge and foot. These are parasitic and need to be hasterly removed which you can inform the LFS owner but don't buy. The little buggers get inside the clam shell. If they are not on the outside you are generally safe.

Hope this helps and all the best on your search

Regards