I just got a Tridanca Crocea clam.
But i did do some research first because i only have PC's on my tank.
From what i have read, you can keep a clam with min. of PC's, from what i read.
I put my clam towards the top of my tank on a flat surface, i'd say it was 3/4's up the tank.
I came down the next morning and he was at the bottom of the tank. I was confused?
So i put him back up and if you're looking directly in front of the tank the mantel was straight front to back. Around 2 hours later, i noticed he was sorta sideways and towards the edge of thew rock. After i did some cooking, playing with my daughter and time with the wife i looked in the tank and he was down on the bottom again. So i moved him to a lower spot in the tank on a piece of dried up faviid, turned upside down so he set in nicely, and that his shell wasn't restricted from opening. Went to bed and came down the next morning only to find the favidd tipped forward and the clam in the sand again?
So i reach in and get him off his side put the mantel upright and set him in the sand.
Now he stays in that spot and from what i can tell, he loves it there. Moderate water flow and decent direct lighting.
I have 192watt PC and a 58g tank, which gives 3.3 w/gal.