I took a close look in my tank where my fish have a spot cleared to the bottom of the tank and there are little microscopic white things crawing around the bottom looking like leaches. I feed them worms and wondering if these are babbies that hatched? Doubt it they would have drowned. Is this a fish fluke? They are light sensitive. Are they harmful to my fish? How do I get rid of them? I am assuming salt. How did I get them? My fish lost their appititites about a couple of weeks ago and dont seem as aggressive and wondering if this is the cause. My fish look healthy just lost thier appitites a little.