I recently joined the forum in hopes of figuring this out. I have an approximately 4K gal koi pond. In my pump basket and my skimmer basket, there are hundreds of these greenish 4mm long eggs or larvae. I don't see any movement, but they're stuck on the baskets pretty good. I have to use high hose velocity to get them off. Can anyone tell me what they are? I appreciate the help. Hopefully, the pics will post.