Well I placed my blue Crocea back in the tank...it looked pretty bad for awhile...but has since turned around. The other (my Teardrop Crocea) unfortunately didnt make it.
Both Clams were in a 20 gallon tank filled up to about 12 gallons. The tank was lit with a single 175 watt 10 k bulb. They were both treated with several weeks of Metronidizole and also subjected to a 2 week period of hyposalinity in which the salinity of the tank was lowered to 1.015. Tank was kept at 80 degrees by a heater. Both clams browned out pretty badly, I'd never seen poop brown clams before.
The blue one seemed to get over the PM easier even though it was the first one to show signs. After a period of 2 weeks w/o showing signs of PM I placed it back in the main tank. Despite being told to do otherwise by Nikki and Mojo, I did not acclimate the clam to the main tank conditions. Instead I just placed it on the bottom of the tank so it could adapt to the increased lighting (dual 250 watt 10k DE's over a 21 inch deep tank). It gaped for the first day, and began to get lighter in color for the first week and a half. It has since regained alot of its color and I expect to be able to put back up where it used to sit (half way up the tank on a ledge) in a week or so. So far I havent seen any signs of PM for about a month in this clam....hoping to stay that way.
I did not acclimate the clam to my tank conditions because I wanted to make conditions as difficult on the protozoans as possible. I was pretty certain the clam would survive, and figured the rapid change in environment might be detrimental to any remaining parasites in/on the clam.
My Teardrop Crocea never made it out of the Q-tank. It was showing more mantle curling almost immediately after I placed the blue Crocea back in the main tank. It began to look worse and worse each day. Finally, it was no longer reactive to light stimulus, (wouldnt contract back into the shell reflexively when a bright flashlight was shone on it, or when the lights were removed to access the tank.) and it did not move at all when I touched the mantle with my finger. I attempted to see if it was still attached to the rock, and discovered that the entire byssal gland had been released by the clam. The byssus was still attached to the rock, but the clam tumbled free, so I removed it from the tank... The clam did not move/react in any way, shape, or form when it tumbled free of the rock or when I removed it from the tank.
So far I'm 50-50 for success vs losses in battling PM. I'm not ever buying clams that originate from Vietnam again....
Just thought I'd share my results in dealing with all of this. Better luck to the rest of you....
Nick