What’s up guys… let’s talk about clams.
Giant clams of the Genus Tridacna are a popular mollusk in reef aquariums.
Most people that aren’t into this hobby are familiar only with the shells of clams.
It’s a shame because their true beauty can only be realized when they are living as they
have a brilliant mantle that is stunning to behold.
Tridacna clam mantles have intricate patterns and come in a variety of colors.
I’ve seen clams that are purple, blue, green, yellow, and even some even have iridescent
qualities.
It is not difficult to understand why these clams are so popular in the reef-keeping hobby.
Tridacna clams are found all throughout the Pacific.
The four most readily available species of Tridacna clams are derasa, squamosa, maxima,
and crocea.
In rare instances one might find the true giant clam, Tridacna gigas.
Here is a 30-year old gigas at the Waikiki aquarium in Hawaii.
It was grown from a tiny specimen less than an inch to this monster that weighs hundreds
of pounds.
There are actually two other species that are not in the aquarium trade namely T. tevoroa
and T. costata which is a new species discovered in the Red Sea.
Let’s talk a bit about their anatomy.
The mantles are filled with zooxanthellae much like photosynthetic coral.
Early in a clam’s life the quantity of zooxanthellae is limited so they rely more on filter feeding.
It is estimated that smaller clams get 65% of their energy from filter feeding.
Larger clams only get 34% of their total carbon from filter feeding indicating a much greater
reliance on photosynthesis.
As a general guideline, clams smaller than 3” would benefit from phytoplankton supplementation.
Lighting is probably the single most important factor to consider when keeping clams.
Second to lighting is the need to maintain tip-top water chemistry.
High calcium and alkalinity are a must.
Clams are known for fast growth rates and deplete calcium and alkalinity aggressively
to power this growth.
This is why they tend to do better in tanks designed for corals like Acropora, which also
require high light and ample supply of major elements for calcification.
As for flow, these clams prefer moderate flow despite originating from shallow areas on
the reef that receive heavy wave action.
The concern with high flow in the aquarium is the risk of introducing bubbles into the
body that the clam cannot effectively eliminate.
Clams have two siphons that move water in and out of its body.
There is a large Inhalent siphon lined by fine tentacles.
When it opens wide, you can catch a glimpse of the clam’s gills.
The gills of the clams are interesting in that they are used for both respiration and
feeding.
The water then is expelled through a smaller exhalent siphon.
The exhalent siphon is also used to expel waste from the clam as well as discharging
sperm and eggs for reproduction.
At the base of the clam is a foot by which it attaches to the substrate.
There is also a byssal organ that excretes a thin byssal threads to anchor it into place.
It is critically important that the aquarist does not damage the foot or the byssal gland
moving a clam from one place to another.
It is easy to damage the byssal organ and if it happens, chances are the clam will die.
Once a clam is anchored to a rock it is best to move the clam and rock together.
Now that we’ve covered the common anatomical features of Tridacna clams, how do we tell
the different clams apart?
Let’s start with Tridacna maxima and Tridacna crocea because they are by far the most similar
to one another.
They both have dazzling multi-colored mantles.
The best way to tell them apart is the shape of their shells.
Maxima clams are slightly elongated in shape while croceas are more stout and stubby.
Also, maxima clams tend to have more pronounced flutes on their shell compared to croces clams
that are a little more smooth in texture.
Crocea clams are called boring clams because they are able to dissolve the nearby coral
substrate leaving only their mantle visible.
At their base they can secrete a mild acid that over the years erodes the calcium carbonate
substrate kind of like how a calcium reactor dissolves media.
Like just about every sessile organism on the reefs, clams are looking to clear out
real estate for their personal growth.
Some have observed that not only are clams capable of releasing a mild acid at their
base to bore down into rock, they are also capable of releasing acid through their extended
mantle to kill off nearby coral.
Tridacna derasa are much easier to tell apart from the other clams.
Derasa clams have a distinctive golden colored mantle with streaks of teal and a vibrant
blue rim.
In comparison to maxima and crocea clams, derasa clams get massive.
It is not uncommon to have a derasa grow to over 20” in a home aquarium.
They are considered one of the more hardy clams making it an ideal choice for a first
time clam enthusiast.
That brings us to Tridacna squamosa.
While less common than the other three clams, the occasional squamosa turns up from time
to time.
Squamosa clams have muted coloration in comparison to maxima and croceas but have a distinctive
fluted shell.
While maximas, croceas, and derasas have somewhat smooth shells, the squamosa has pronounced
scales that are quite attractive in their own right.
One day I would like to try and aquaculture clams.
We are a long way off from doing anything like that, but they are such cool animals
and it is possible to get them to reproduce sexually by manipulating light, hormones,
and chemical parameters in the water.
Most of the places doing it now are doing it with mariculture setups out in the ocean
or hybrid facilities on the coast.
I think in the next few years there will be a lot of progrWhat’s up guys… let’s
talk about clams.
Giant clams of the Genus Tridacna are a popular mollusk in reef aquariums.
Most people that aren’t into this hobby are familiar only with the shells of clams.
It’s a shame because their true beauty can only be realized when they are living as they
have a brilliant mantle that is stunning to behold.
Tridacna clam mantles have intricate patterns and come in a variety of colors.
I’ve seen clams that are purple, blue, green, yellow, and even some even have iridescent
qualities.
It is not difficult to understand why these clams are so popular in the reef-keeping hobby.
Tridacna clams are found all throughout the Pacific.
The four most readily available species of Tridacna clams are derasa, squamosa, maxima,
and crocea.
In rare instances one might find the true giant clam, Tridacna gigas.
Here is a 30-year old gigas at the Waikiki aquarium in Hawaii.
It was grown from a tiny specimen less than an inch to this monster that weighs hundreds
of pounds.
There are actually two other species that are not in the aquarium trade namely T. tevoroa
and T. costata which is a new species discovered in the Red Sea.
Let’s talk a bit about their anatomy.
The mantles are filled with zooxanthellae much like photosynthetic coral.
Early in a clam’s life the quantity of zooxanthellae is limited so they rely more on filter feeding.
It is estimated that smaller clams get 65% of their energy from filter feeding.
Larger clams only get 34% of their total carbon from filter feeding indicating a much greater
reliance on photosynthesis.
As a general guideline, clams smaller than 3” would benefit from phytoplankton supplementation.
Lighting is probably the single most important factor to consider when keeping clams.
Second to lighting is the need to maintain tip-top water chemistry.
High calcium and alkalinity are a must.
Clams are known for fast growth rates and deplete calcium and alkalinity aggressively
to power this growth.
This is why they tend to do better in tanks designed for corals like Acropora, which also
require high light and ample supply of major elements for calcification.
As for flow, these clams prefer moderate flow despite originating from shallow areas on
the reef that receive heavy wave action.
The concern with high flow in the aquarium is the risk of introducing bubbles into the
body that the clam cannot effectively eliminate.
Clams have two siphons that move water in and out of its body.
There is a large Inhalent siphon lined by fine tentacles.
When it opens wide, you can catch a glimpse of the clam’s gills.
The gills of the clams are interesting in that they are used for both respiration and
feeding.
The water then is expelled through a smaller exhalent siphon.
The exhalent siphon is also used to expel waste from the clam as well as discharging
sperm and eggs for reproduction.
At the base of the clam is a foot by which it attaches to the substrate.
There is also a byssal organ that excretes a thin byssal threads to anchor it into place.
It is critically important that the aquarist does not damage the foot or the byssal gland
moving a clam from one place to another.
It is easy to damage the byssal organ and if it happens, chances are the clam will die.
Once a clam is anchored to a rock it is best to move the clam and rock together.
Now that we’ve covered the common anatomical features of Tridacna clams, how do we tell
the different clams apart?
Let’s start with Tridacna maxima and Tridacna crocea because they are by far the most similar
to one another.
They both have dazzling multi-colored mantles.
The best way to tell them apart is the shape of their shells.
Maxima clams are slightly elongated in shape while croceas are more stout and stubby.
Also, maxima clams tend to have more pronounced flutes on their shell compared to croces clams
that are a little more smooth in texture.
Crocea clams are called boring clams because they are able to dissolve the nearby coral
substrate leaving only their mantle visible.
At their base they can secrete a mild acid that over the years erodes the calcium carbonate
substrate kind of like how a calcium reactor dissolves media.
Like just about every sessile organism on the reefs, clams are looking to clear out
real estate for their personal growth.
Some have observed that not only are clams capable of releasing a mild acid at their
base to bore down into rock, they are also capable of releasing acid through their extended
mantle to kill off nearby coral.
Tridacna derasa are much easier to tell apart from the other clams.
Derasa clams have a distinctive golden colored mantle with streaks of teal and a vibrant
blue rim.
In comparison to maxima and crocea clams, derasa clams get massive.
It is not uncommon to have a derasa grow to over 20” in a home aquarium.
They are considered one of the more hardy clams making it an ideal choice for a first
time clam enthusiast.
That brings us to Tridacna squamosa.
While less common than the other three clams, the occasional squamosa turns up from time
to time.
Squamosa clams have muted coloration in comparison to maxima and croceas but have a distinctive
fluted shell.
While maximas, croceas, and derasas have somewhat smooth shells, the squamosa has pronounced
scales that are quite attractive in their own right.
One day I would like to try and aquaculture clams.
We are a long way off from doing anything like that, but they are such cool animals
and it is possible to get them to reproduce sexually by manipulating light, hormones,
and chemical parameters in the water.
Most of the places doing it now are doing it with mariculture setups out in the ocean
or hybrid facilities on the coast.
I think in the next few years there will be a lot of progress made on trying to grow clams
inland and I personally think it would be an exciting project.
Anyhow, that does it for Tridacna clams.
I hope you guys enjoyed the video.
Until next time, happy holidays, and happy reefing.
ess made on trying to grow clams inland and I personally think it would be an exciting
project.
Anyhow, that does it for Tridacna clams.
I hope you guys enjoyed the video.
Until next time, happy holidays, and happy reefing.