What is the bubbly scum on top of my outdoor pond that has 5 goldfish in it and a 2 medium sized spider plants?

Hi I used to have the same problem with an outdoor pond. If fish come to the surface alot its cause their not getting enough air. or their pooping soo much that theres too much ammonia. You can get cheap pumps for any gallon of container you have for 30$ or less at walmart, you need air pumping in there if you have fish in any situation they breath air too... Also whithout moving water you get scum at the surface even a bubbler would help. Trust me the more chemicals you use the more you will need go as natural as you can, and buy an ammonia tester and something to give your fish air You know those 10itre bottles of water they sell at grocery stores buy two put some salt in and fill your containers with water, and let sit for 2 days so the chorine evaporates and change the water in your thingy with the fish and plants every week.(25% water change) every week)

DON'T USE CHEMICALS.. Fish don't need "conditioning" etc.. it's just more junk you don't need. Goldfish tend to be at the surface even in a clean pond. They are constantly hungry and 'begging' for food. but those thousands of bubbles sound like there's something decaying in there. Stop feeding them for a couple of days and scoop up to a third of the water from the pond. If it's too much work, buy a pump. You'll be needing one in the future. Owning a pond is not just looking and feeding, it has to be cleaned occasionally and water changed like a tank in your house.