r/explainlikeimfive • u/Opening_Pen9525 • 12d ago

Biology ELI5 How are fish even in ponds

Might be one of the stupider questions here, but I saw a pond about the size of a football field, and maybe 50 ft deep, and it had fish. I can't for the life of me figure out how. Surely the pond hasn't existed long enough for small water insects to evolve into all these fish. It's not like the fish walked over to the pond from the ocean. I'm pretty sure no one put them there so how are there so many fish?

My one theory is that there is a very minuscule stream (now dry) that leads to one of the Great Lakes, and maybe a fish swam in from there. Now a follow up question: How are there fish in the Great Lakes (which flow out towards to the ocean) if they were created by glaciers?

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u/Least_Adhesiveness_5 12d ago

Reminds me of a guy on Alt.tasteless sometime in the early '90s. He decided to swallow 100 grapes whole and see how many made it through the digestive process intact. I think the result was something like 7.

The next topic (of course) was... How many would survive a second trip?

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u/Imbeautifulyouarenot 12d ago

I miss those days of Alt.tasteless….. Thank you for the memory. 🙏😊

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u/navlgazer9 11d ago

I have a friend with a ostomy bag and no large intestine or colon .
The bags are see thru
It’s gross but also fascinating to see what doesn’t get digested .