From what I can see, those look like my FAVORITE plant, Fairy Moss, also known as azolla.

Anne

So I should leave them alone then? They seem to proliferate pretty fast, I can see my pond getting covered with them soon. Do they drown out other plants, or are they nice team players? Thanks,

They have always been nice team players for me, but then I am in a much colder climate and my fish like to nibble on them so I am always wanting them to grow more. Maybe someone from zone 9 can chime in to let us know how they behave there.

Anne

Here in Zone 7 they are good to have especially if you get alot of sun. They help block out some of the rays and that controls algea growth. My ponds get completely covered in it and it turns a pretty red color after awhile. Mine dies back during the winter and usually returns the next year (with the exception of this past winter being the first that it did not come back but it was very cold for a very long period). I love it, so I ended up buying a cup full off of Ebay just so I could get going again. Hope this was helpful.

I only have 1 goldfish, so the "food" is way oversupplied for the demand. I didn't really want too many fish, but maybe a few more won't hurt.

Thanks,

Mine got into my pea gravel bog and multiplied like crazy, because there was nothing to eat them. Then one day in mid summer they started dying back. Too much shade or other plants used up all the nutrients in the water. I hoped it wasn't anything bad - I didn't have any other problems.