Adding a clam - Help before purchase

[Iceman9128]

Looking to add a clam to my 25 gal. tank. I have 2X65 watts power compact lighting. My water parameters are within range except for ammonia which are a little high. I can't find a good reason for this as the tank is not new. I've had it running for 7 years.

I've read that clams use ammonia.

Looking for some info on clams be fore I by one. I was looking probably at a squamosa.

Any info would be great.

Rheal