I have Caulerpa Cupressoides and other macro algae in the tank. But, the problem/question is resolved. The critter was crawling on the front glass. As I was trying to get better pictures of it, my shrimp brushed over it and dislodged it. As it fell through the water it shortened, flattened and widened like a 3/4x1/2 inch ribbon. My female O. Clown grabbed it and ate it. All gone. Thanks everyone. :-)