I have an outbreak of what I thought was Argulus (carp lice). Small diameter clear shell 1/16" approx, clear tanish body under the shell, on the head of the body two "eyes" and two antenna. The body undulates like a clam foot. The antenna move in and out like a clam. I looked under a scope and the body looks like a clam and the shell has rings like a clam. Any ideas what this might be?