Jump to content
Sign in to follow this  
stylaster

Giant clams as biofilters

Recommended Posts

I have been doing this for years. Get a medium sized derasa (8-10") per 50g or so will do a great job in nitrate and phosphate reduction, of course depending on your bioload. I personally have a 10" deresa, a 4" maxima and 5" crocea in my 120 with 3 fish and have no detectable nitrates or phosphates. Something to think about for those of you fighting nitrate / phosphate issues. Also here is an interesting article about it

 

http://www.aquasearch.net.au/aqua/clambiofilter.htm

Share this post


Link to post
Share on other sites

I have been wanting one, I would have to re-home my flame angle though... And then I would have to cross my fingers because my giant RBTAs kill everything! :(

Share this post


Link to post
Share on other sites
I have been wanting one' date=' I would have to re-home my flame angle though... And then I would have to cross my fingers because my giant RBTAs kill everything! :([/quote']

 

One reason I'm going no nems.. It's hard but almost not worth it. Real beauties but te fact they sometimes like to walk and go on a homicidal coral spree sucks :( and I love dwarf angels just like corals more or I would have one lol

Share this post


Link to post
Share on other sites

Dude there are always other options besides breaking it down. GFO, Carbon Dosing, Skimmer, Macro Algae etc, etc, etc.

 

I thought Clams were immune to Nem stings?

Share this post


Link to post
Share on other sites

Most clams can handle nem stings... I have a 18" or so gigas clam that has a rose BTA attatched to its side directly and they are both doing fine!

Share this post


Link to post
Share on other sites

ya i have never had any issues with zoas, clove polyps, sps or lps corals stinging clams. If they do its pretty easy to tell, cause the clam mantle will retract from the area that's getting stings. Best to then move the clam or offending coral / anemone

Share this post


Link to post
Share on other sites
Dude there are always other options besides breaking it down. GFO, Carbon Dosing, Skimmer, Macro Algae etc, etc, etc.

 

I thought Clams were immune to Nem stings?

 

I wasn't saying nems and clams as I can't pull an IME cause I've PERSONALLY never had either myself. The nems killing thing reference was just to corals, stonies etc

Share this post


Link to post
Share on other sites

Hmmmm. I haven't done enough research about it, but a lot of people are keeping clams in nano aquariums. I wonder if I could keep a small one in my 10 gallon. Probably not long-term. I already have to dose for alk.

Share this post


Link to post
Share on other sites

If you stick with crocea would work fine max size i have seen in that species is 8" or so. You could get away with a maxima too they top out at 12-14" Down side is you better have some sort of calcium, alk constantly going into the tank lol

Share this post


Link to post
Share on other sites

That was an interesting read. Thank you for posting it up.

 

I have been seriously concidering getting a derasa clam. I have read that they are a good starter clam. Do you have any tips for a newbie to clams. What should I look at to see if its a healthy specimen. Is there a better place to purchase one or does everyone basicaly get them from the same source.

 

Sorry to pick your brain on your thread. You seem to be the clam guru in these parts :)

Share this post


Link to post
Share on other sites

Ya deresa is a great starter clam, they can get along fine under t-5 in the bottom of a two foot deep tank without issue. Look for good mantle extension, check to make sure the inhalant siphon (mouth) isn't gaping. Check the bottom of the clam for rice snails (small white snails about 2-4mm long) Check to make sure the byssus opening isn't torn or byssus threads hanging out( opening in the bottom of the clam). Its ok if there are small rocks in there that's what the clam has attached to. The clam should respond to you passing your hand over it by closing slightly or all the way.

Most of the saltwater stores around carry clams and i have never had issue with getting them from any of them. All seem to be healthy

Your choice in deresa is tiger stripe (fine goldish lines across the mantle) or standard which is brown with white blotches and blueish rim. Make sure you get one that is atleast 3" in length and you should be good to go.

Placement for this species of clam is on the sand bed, or bottom of the tank. They dont like rock work much and will tend to rock and fall off.

 

Potential clam issues are angels and pygmey angelfish. Any kind of goby that would deposit sand on the clam. Watch the clam for the first few days to make sure no other fish or inverts takes any interest in the clam and picks at it

Share this post


Link to post
Share on other sites
Ya deresa is a great starter clam, they can get along fine under t-5 in the bottom of a two foot deep tank without issue. Look for good mantle extension, check to make sure the inhalant siphon (mouth) isn't gaping. Check the bottom of the clam for rice snails (small white snails about 2-4mm long) Check to make sure the byssus opening isn't torn or byssus threads hanging out( opening in the bottom of the clam). Its ok if there are small rocks in there that's what the clam has attached to. The clam should respond to you passing your hand over it by closing slightly or all the way.

Most of the saltwater stores around carry clams and i have never had issue with getting them from any of them. All seem to be healthy

Your choice in deresa is tiger stripe (fine goldish lines across the mantle) or standard which is brown with white blotches and blueish rim. Make sure you get one that is atleast 3" in length and you should be good to go.

Placement for this species of clam is on the sand bed, or bottom of the tank. They dont like rock work much and will tend to rock and fall off.

 

Potential clam issues are angels and pygmey angelfish. Any kind of goby that would deposit sand on the clam. Watch the clam for the first few days to make sure no other fish or inverts takes any interest in the clam and picks at it

 

Thank you for the great info (clap) I am looking forward to getting one. They are not as pretty as the maximas but they are still very nice looking animals.

 

I do have a sand sifting goby so I will be sure to place the clam away from the goby's burrow, good heads up.

Share this post


Link to post
Share on other sites

Well, this is interesting.

 

Did some reading and it looks like clams keep their zooxanthellic symbionts nutrient limited to force them to pump out sugar, just like coral. The clams' resident population of zooxanthellae doesn't significantly ramp up in response to increased nutrient levels, but on the other hand, clams do respond positively to NH3 and PO4 enrichment -- moreso than feeding them algae, their normal food. Turns out PO4 is necessary for shell growth, which can be limited by either PO4 or Ca levels.

 

On the downside, nutrient consumption by juvenile giant clams is described as "limited" and worse, there's some evidence that what may be going on here is that clams are improving the coupling between the pelagic and benthic environments -- that is, they're facilitating the movement of nutrients out of the water column and into the substrate. Basically, by absorbing nutrients (which they will continue to do even when their growth is limited by insufficient light) and excreting their feces onto the surface of the substrate, they're concentrating the available nutrients and making it easy for the bacterial community in the substrate to access them. From what I gather, however, oysters and mussels are much bigger offenders in this regard than clams -- in low light, clams will reduce their nutrient uptake, while oysters will go right on sucking in everything they can get and excreting what they don't need as "pseudofeces".

 

But it was also noted in one paper that "it is known that several specimen being kept in one aquaria are able to deplete nutrient values considerably" -- and that conclusion dates back to 1994, so the aquaculture guys have obviously been hip to this for quite some time. You gotta figure that if they've signed off on it, it's probably a viable technique that we should be thinking about stealing... Though I do worry that the aquaculture crowd isn't oriented towards "permaculture" setups like we are -- their goal is typically short-to-medium term maximization of biomass output, and then they reset the system after each batch gets sent to market. Improving benthic/pelagic coupling (ie, increasing the rate of P accumulation in the substrate) may not be an issue for them.

 

Anyway, if anybody wants to get all science-y about this, the most relevant and accessible paper I found is here: Physiological performance of giant clams (Tridacna spec.) in a recirculation system by A. Kunzmann, from the Proceedings of the 11th International Coral Reef Symposium, July 2008

  • Like 1

Share this post


Link to post
Share on other sites

In my experience when adding a new clam you shouldn't expose them to air, and SLOWLY drip acclimate them to your system it may be preferable to test the all in the bag and adjust your tank alk to as close to the same level as you can. Even if you wait a day or two and leave the clam at your LFS while you raise you levels to match. In my experience

Share this post


Link to post
Share on other sites

Lots of clams that I get come in damp bags. They almost always do real well. I think it has a lot to do with how they are exposed.

 

I am excited to see that more people are seeming to get back in to clams. They are perhaps one of the most beneficial an beautiful inverts that we can add to our reefs. I should have a bunch coming in on Monday and it will be interesting to see what colors and variations arrive. I get all giddy when a new clam order comes in lol.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×