Hey Malisa. I was never able to keep a clam in that tank when I had it. I have had clams in all of my tanks, but for some reason was unable to keep one in that setup. I tried with a Derasa (that I kept in a 29G for years), a Squamosa (that I also had for over a year in the 29G), and a Crocea. I am not sure what the problem was, but they always quickly declined. I gave all of them away when they looked sick and all recovered after a few days in other tanks. I am keeping a crocea in my 24G right now and it is doing great. The only difference in your tank and all of my others was a refugium. I am not sure if it had anything to do with it, but it might have.