These things are very small, crawl on the glass, swim in the water column, and can be VERY fast, and move in a jerky motion like a water flea. I have no idea what they are. I can't see them with the naked eye. I hope they're not hydra...?!?? I have lots of them, so if they are good, then maybe they are good food for fry, and hopefully not the other way around. So far, I have killifish fry growing from eggs laid in the tank with the parents, and I haven't been feeding the fry anything, just been taking care of the parents needs. Susan _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member