i just want to add a few things.
the article listed at the top is not accurate. i wouldn't expect DT's to keep an article on there web site that wasn't favorable to phytoplankton
clams are not dependent on filter feed phyto. they are primarily photosynthetic and can sustain themselves on the food provided by there zooxanthellae, through light alone. clams will extract dissolved nitrogen and phosphorus from the water and pass onto there zoox and then the zoox gives the clam sugars as food. clams will filter phyto (and bacteria and zooplankton) but when they do this all they are doing is extracting the same N & P and passing it to the zoox.
one of the arguments of that article is that clams mantles are not fully developed untill they are 4" in length. this is completely false. clams mantles are fully developed and full of zoox within week of metamorphosis. it also says that clams mantles are not large enough to house enough zoox to support the clam untill its 4", false again. the size of a clams mantle is proportionate to the size of the clam through out its life.
another argument some people have for feeding phyto is that clams have a fully functioning digestive system and that if they didn't need to feed they wouldn't have this. so lets look at this. clams gills are multifunctional, they are use for respiration and capturing particulate matter. they can get rid of the gills or they wouldn't be able to breath , clams also constantly replenish there zoox, they use their gills to do this.
the stomach is connected to the zooxanthellae tubular system (where the zoox live) the stomach passes new zoox from the gills to the ZTS , processes the sugars the zoox make (to feed the clam) and pass old, dead and un-viable zoox to the anus.
even though the digestive system isnt needed for filtering phyto, it is still used as a basic function of the clam.
if you want to feed your clams phyto, go ahead. but dont think that they will die if you dont. as long as you have strong light and N & P (fish pee and poo) in the water the clam will do just fine !
