Underwater Snail Timelapse

I got some great underwater footage of some Snails and some small minnows. Shot in 4k with Osmo Action Camera. When I upload to 3Speak I notive my footage becomes very pixilated and noisy. Any suggestions on how to fix this would be greatly appreciated as my footage is very crisp and clear when viewing the original footage. You can see how shallow the tidal pool is at the very end when I stop the footage and this is at low tide.

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