A light coating of Pam cooking spray will suffocate the aphids. It's completely harmless to your other pond critters. Spray the waterlilies late in the day (when there's no chance for the sun to burn them) - let it sit 15 min or so and then rinse off with your garden hose. There will be a bit of an oil slick, but your skimmer will take care of it in a few minutes. It'll dissipate soon enough even if you don't have a skimmer. One treatment lasts a while: I usually have to do this 2 or 3 times per season, but haven't seen any aphids this year. Good Luck.

Your "worms" are millipedes. They should be harmless to the plants. I have no idea what the black dots might be. Any chance for a picture of that? Is you strawberry actually having any problems - poor color, poor growth, etc.??

Tracey is correct. They appear to be ladybugs in the pupal stage. Pupae will eventually shed those cumbersome skins and emerge as fully adult ladybugs. You will be able to recognize those, I'm sure.

"The fungus gnats could be at the bottom of your problems. They are difficult to eradicate, much simpler approach could be to start a new plant from cuttings." You can, and I would try a cutting. They're easy to take from these. But you can get rid of fungus gnats, too. It's worth a shot. Mix 1 part hydrogen peroxide (3%) to 4 parts water. Water the plant thoroughly with it. This kills the larvae (most of them, anyway) and newly-hatching eggs. You may need to repeat this if you start seeing a few gnats again. It's not 100% reliable. Reports that it trims tiny feeder roots are unknown, but it probably does; the plants I've used it on seem to do just fine and if there's any stress, it's not obvious. Trap the adults with a dish or small bowl of apple cider vinegar, or a fly strip. Neem oil spray or a very mild insecticide rated for indoor use will also work. With Neem oil, mind cats, or if you're pregnant: http://npic.orst.edu/factsheets/neemgen.html It's not quite so harmless as most people assume, but close.