I did not dip it before putting in tank, but did dip it a few weeks afterwards - mid Dec. I used CoralRx and saw a few little swimmers fall off. The bottle i bought from LFS actually "expired" the day i bought it and was able to exchange it today -- so i dipped again and about 7 very tiny grey things fell off again.
These maroon things seem to be organic and not animal. (not sure if i am using correct use of words here, but hopefully it makes sense.)