Significantly less macroscopic life. If it's a very small body it is likely to dry up eventually, so that rules out long-lived fully aquatic lifeforms. Even pr

Significantly less macroscopic life. If it's a very small body it is likely to dry up eventually, so that rules out long-lived fully aquatic lifeforms. Even predatory insect larvae (for example, dragonfly larvae) have a much longer development cycle than mosquito larvae, so you won't find them in a body of water that will only be around for a few weeks. The other factor is oxygen... even a still pond that exists year around will have much lower oxygen levels than moving water, and that's a significant limiting factor for aquatic life. Mosquito larvae are air-breathers (they rest just under the surface and have a "snorkel" that breaks the surface to breathe) so they can live in almost completely hypoxic water so long as there is microbial life for them to eat.