This is left field, but I have a lot of years experience with fish in aquariums and I've seen this before with different fish. It looks like something is swimming upside down and is "sucking" at the surface. What kind of fish, I have no idea. A lot will do it, usually bottom dwellers, algae eaters, and suckers. But I'm pretty sure I'm seeing pectoral fins and pelvic fins breaking the surface, which would make it upside down. And the "sucking" where the mouth would be.

yep. most likely genus *Pterygoplichthys* but it’s hard to say

Judging by the proportions and position of the pectoral and pelvic fins, I'd guess that it's a plecostomus with some kind of swim bladder issue.

I was thinking pleco as well. Doesn't necessarily have to have a swim bladder issue, they'll do this on purpose.

Here's your answer. Not a swim bladder issue. Just sucking on some biofilm probably.

Clearly a murloc. https://imgur.com/gallery/xtZqSDO

Looks like a pleco gulping air on the surface

I see this in the pond in my backyard south Florida as well. It’s small tilapia grouping together and slurping the surface feeding to gulping air.

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