Sounds like bluegreen algae. The warm weather and the sun being out the last couple of days probably caused the bloom. The water must be full of nutrients too. Their are probably water treatment plants that discharge into the creek or runoff from farmland with a lot of fertilizer or a lot of farm animals that live on the land. I wouldn't think that would be good for fish that spawn in the headwater areas. Probably a little toxic to the fry. Was the water flowing much? Sounds like it wasn't.