Turtlesteve
New member
I am posting this to offer my experience with freshwater dipping of clams and hopefully to get some helpful feedback....
First, the facts:
The first freshwater dip was on Dec. 3, 2002. The two clams in this dip, a 3" t. crocea and a 2.5" t. squamosa, that had been showing symptoms of a "disease" for two weeks. This dip was 80% DI water for 25 minutes.
I have no idea what caused this "disease." At first the edges of the mantle became wrinkled and pinched in at places, and the mantle began to expand less than normal. Once a spot on the mantle pinched, it did not return to normal until after the dip. After two weeks, the clams' mantle expansion was about 50-60% of normal. Neither clam opened past 1/8" during the dip.
Within 20 hours after the dip, both clams were expanding at nearly 100%.
The clams continued to look perfectly normal and showed good growth until about 3 weeks ago. Then the condition re-appeared, but progressed more slowly than the first time. This time, after 3 weeks i would say mantle expansion was at about 60% for the two clams. Both clams re-developed the condition at the same time. I dipped both clams again yesterday afternoon, for 20 minutes in 90% RO/DI water. Within 24 hours, the crocea is looking completely normal, and is expanding at about 90%. The squamosa, however, opened and closed violently several times while in the FW dip. I suspect that this exposed the clam's vital organs to the freshwater, rather than just the mantle edges as on the crocea which stayed mostly closed. For the first 12 hours, the squamosa showed no mantle expansion, extreme gaping and did not respond to light (but did respond to movement). 24 hours after the dip, the squamosa is still not expanding much (30%), but now responds to changes in light. I am still unsure of whether or not this clam will survive.
Some hypothesises:
The 2nd time the clams developed the condition, occured at the same time my tank experienced a major dinoflagellate bloom. This could be significant, as a change in water parameters might have weakened the clams to the point of re-contracting this "disease."
I have considered the possibility of predation on the clams by snails, or other pests, but to me that seems unlikely because, the pinching dissapears completely after a freshwater dip, and pinched areas did not heal on their own, with time.
Also, it seems to me that any moderately healthy clam can survive a freswater dip, provided that it does not open completely in the freshwater. I would suggest, that if you are freshwater dipping clams and they open completely, to remove them immediately and put them back into the tank.
First, the facts:
The first freshwater dip was on Dec. 3, 2002. The two clams in this dip, a 3" t. crocea and a 2.5" t. squamosa, that had been showing symptoms of a "disease" for two weeks. This dip was 80% DI water for 25 minutes.
I have no idea what caused this "disease." At first the edges of the mantle became wrinkled and pinched in at places, and the mantle began to expand less than normal. Once a spot on the mantle pinched, it did not return to normal until after the dip. After two weeks, the clams' mantle expansion was about 50-60% of normal. Neither clam opened past 1/8" during the dip.
Within 20 hours after the dip, both clams were expanding at nearly 100%.
The clams continued to look perfectly normal and showed good growth until about 3 weeks ago. Then the condition re-appeared, but progressed more slowly than the first time. This time, after 3 weeks i would say mantle expansion was at about 60% for the two clams. Both clams re-developed the condition at the same time. I dipped both clams again yesterday afternoon, for 20 minutes in 90% RO/DI water. Within 24 hours, the crocea is looking completely normal, and is expanding at about 90%. The squamosa, however, opened and closed violently several times while in the FW dip. I suspect that this exposed the clam's vital organs to the freshwater, rather than just the mantle edges as on the crocea which stayed mostly closed. For the first 12 hours, the squamosa showed no mantle expansion, extreme gaping and did not respond to light (but did respond to movement). 24 hours after the dip, the squamosa is still not expanding much (30%), but now responds to changes in light. I am still unsure of whether or not this clam will survive.
Some hypothesises:
The 2nd time the clams developed the condition, occured at the same time my tank experienced a major dinoflagellate bloom. This could be significant, as a change in water parameters might have weakened the clams to the point of re-contracting this "disease."
I have considered the possibility of predation on the clams by snails, or other pests, but to me that seems unlikely because, the pinching dissapears completely after a freshwater dip, and pinched areas did not heal on their own, with time.
Also, it seems to me that any moderately healthy clam can survive a freswater dip, provided that it does not open completely in the freshwater. I would suggest, that if you are freshwater dipping clams and they open completely, to remove them immediately and put them back into the tank.
