Tridacna Maxima Clam

[jeasko]

well was going to look for a croceas, but ended up with a derasa as went into LFS and this little fellow was just sparkling at me, so who was I to resist.

might not be a vibrant as the maxima or croceas but still seems to pack a punch with its colours in my tank!

 

[Lynden]

Needs to be in the sand bed. Otherwise, looks good.

 

[jeasko]

Lynden

Have been told mixed things about thier location as the derasa's seem to be either embeded in a natural hollow/crevice or in the sand bed, being that my lighting (2 x 39w 34in t5 with arcadia reflectors and 2 x t8 blue) will prob do it no favours at the bottom of my tank (approx 16 inches from the surface) i placed it high up on the rock.

this is just but one site that says this
http/www.reefcorner.com/SpecimenSheets/derasa.htm

 

[andywg]

Ronald Shimek notes in Marine Invertebrates that

Most individuals in nature are found on hardpan substrates, but some are found in sand. Small individuals of less than 4in (10cm) get most of their nutrition from phytoplankton filtered from the water, so the clam needs consistent feedings of phytoplankton, preferably of different types.

 

[Musho3210]

Are they parablolic reflectors or just flat sheets of metal? If the former, you are likely to be fine as far as lighting needs.

Please encourage everyone to forget watts/per gallon, it is an old school rule of thumb that is far from useful and very miss-leading.

Agreed. Just make SURE you place it high-up in your rock stack as maxximas are one of the higher-light requiring clams. IMO, Crocea or Derasa would be more-suited to your tank.

arent croceas more light demanding than maximas? I know they are around the same league, but ive always heard croceas to be that little bit more.

 

[Adrinal]

The short answer is most all these clams are collected in the first 5 meters. Numbers drop of dramatically after that.
Derasa is the only exception to this. The difference between light in Crocea and maxima is nominal. The problem with Maxima is they are collected to early IMO. While the notion that you need to feed a baby clam is wrong, baby clams still have a harder go at it.
(the fact is the smaller the clam the more surface area per volume of flesh.

Giant Clams
Great read.

 

[jeasko]

so should i leave me derasa where it is or place it on the substrate?

I have taken the decisision to place it on the substrate even though it is approx 14" from the surface of the water as i feel it is probably the safer place to position it, however I am concerened that under twin t5 arcadia marine white with parabolic reflectors and 2 t8 blue tubes that the lighting is not sufficient for it, being that I have concerns over this I have kept an eye on it today and it seems fine its fully opened and the mantle is extended way beyond the shell and all appears ok so not sure if its still to deep for the calm to get enough light

 

[rhysiboy]

i know your past the lighting bit but personaly i think that 4 T5 HO's is the minimum for clams and the sort buut thats personal opinion. The dersea looks amazing so ya better take good caare of it If your worried about lighting theres an amzing new product in the uk - Hagen GLO T5HO, they are twin starter units and are surprisingly well priced if you look in the right places... cough cough ebay

 

[andywg]

While the notion that you need to feed a baby clam is wrong,

Do you have anything to support that? Dr Ronald Shimek is a very well respected researcher who spends his days researching how appropriate invertebrates are for keeping in aquaria and as such is highly regarded with his advice.

 

[jeasko]

still not convinced i need more lighting for the derasa clam as it appears to still be doing well, when I got the clam I picked up some food for it as well, so feeding wont be a problem, this does just seem to be one of those subjects where there are no hard and fast rules

Before heading out to buy as you all know I did some research which actually helped me to make a decision to buy, mostly because in the uk ALL clams have to be aqua cultured and are not to be taken form the ocean. SO will continue to monitor and update you all as I go.

Currently I took the decision to place it on the substrate as i was concerned it wasnt in a securelocation, which means it is positioned approximately 14" from the surface of the water to the bottom of the clam (will take some pics when i next get a chance) as of this morning even under just the blue t8 tubes the derasa is half open which must be a good sign.

 

[Adrinal]

i know your past the lighting bit but personaly i think that 4 T5 HO's is the minimum"

How much PAR do you estimate that is in his tank? How much PAR do you think saturates a Derassas host algae growth needs?

 

[Adrinal]

While the notion that you need to feed a baby clam is wrong,

Do you have anything to support that? Dr Ronald Shimek is a very well respected researcher who spends his days researching how appropriate invertebrates are for keeping in aquaria and as such is highly regarded with his advice.

Other than the clam speakers at IMACs & MACNAs and the book Giant Clams... reputed to be the most up to date info on our floppy friends, nope haven't done other research myself... personally. If I recall the last Shimek speach I attended he has changed his tune on this subject as well, don't quote me. You could send him an email though. Anyone know which board he is on now?

still not convinced i need more lighting for the derasa clam as it appears to still be doing well, when I got the clam I picked up some food for it as well, so feeding wont be a problem, this does just seem to be one of those subjects where there are no hard and fast rules

Before heading out to buy as you all know I did some research which actually helped me to make a decision to buy, mostly because in the uk ALL clams have to be aqua cultured and are not to be taken form the ocean. SO will continue to monitor and update you all as I go.

Currently I took the decision to place it on the substrate as i was concerned it wasnt in a securelocation, which means it is positioned approximately 14" from the surface of the water to the bottom of the clam (will take some pics when i next get a chance) as of this morning even under just the blue t8 tubes the derasa is half open which must be a good sign.

If it is happy, leave it.
Its less important that the Derasa is on sand, than the Crocea and Maximas are on a rock(and preferably not one too big so you can move it around after it attaches if need be).

 

[andywg]

Other than the clam speakers at IMACs & MACNAs and the book Giant Clams... reputed to be the most up to date info on our floppy friends, nope haven't done other research myself... personally.

If I recall the last Shimek speach I attended he has changed his tune on this subject as well, don't quote me.

It would seem a fairly swift change of heart since the book only went to press in 2004, but if research has come out I would expect a scientist to be one of the first to change their views.

I wonder if any studies have been done which involve fringe level lighting (such as we might use, rather than powerful MH lights) and any difference in growth/survival rates of the clams. I guess at the end of the day the people who are actually farming the clams are some of the best people to observe.

 

[jeasko]

IMO (not that i know a great deal about these things) even the experts on this subject are a little uncertain of thier findings as there are discrepancies from one expert to another and generally there seems to be very little solid information on how to look after these jewels of the ocean, about the only consistant information is regarding the make up of these things ie the zooanthalae and such like.

There also seems to be (not sure how true the posts are on different sites on the net) no common ground for those that choose to keep them as to the best thing for them, some people feed very little or not at all some feed everyday, some people keep them under very little light and some vice versa, so as adrinal says it seems happy so I am going to leave it be for now as disturbing it agin will surley stress it.

One other thing I wouldlike to know is whats the first sign things are going wrong? having done some home work on them most people sem to say that the mantle stops extending so far when its unhappy and that this is the first sign things are wrong, is this correct or does someone else have any other ideas what to look out for?

Looks like ive opened a real can of worms here sorry guys!

 

[SkiFletch]

Well, first off, if it does not like being in the rock work it will tell you... Clams not happy with being in rocks will use their feet to push themselves off the rocks. So if you find it in the sand in the next couple weeks, best to leave it there

Secondly as for signs of trouble, there are 3 things to watch out for with clams. First, pinched mantle; the clam will not open its shell completely and will pinch the mantle flesh in its opening. Try training it by squirting freshwater at it to get it to retract and see how it re-opens. Second, pyramellid snails (I think that's what they're called); these tiny white snails will eat clams and irritate them to death. They live around the clams foot and are tiny, white conical shelled snails. Dips in iodine and flatworm exit can kill these. And lastly, gaping shell. This condition is usually terminal as the clam can no-longer keep its shell closed due to weakness. Wish there were more you could do about this, but usually by the time a clam gets there, its too late.

Edit: And since it was mentioned earlier in the thread, all clams sold in the US also must be cultured. There are gigantic clam culture facilities at many locations around the globe for this purpose. Its a true success story about regulation and propagation safeguarding an organism