Raising Rotifers

to those who don't know (yet). Rotifers are bout the only thing newly hatched clown fish fry will eat.

OK, so i have rotifers. in an airiated bucket with correct salt density and rotifer diet and lighting.

So big question is..how do i know my rotifers are actually multiplying?

Sure after a couple of days the green hue in the bucket (from rotifer diet) does get lighter...however since the little buggers are microscopic..how am i to tell i'm actually producing something?!!

I'm currently going thru all the motions of "harvesting" and blah blah..water changes blah blah....still...how do i know?