https://ourworldindata.org/data-insights/almost-all-livestock-in-the-united-states-is-factory-farmed
Estimates are still quite high globally too. Around 94% of all globally farmed animals are factory farmed. 74% of all farmed land animals are factory farmed and virtually all farmed fish
100% of farmed fish, too? Get outta town!
Treat that more as a rounded figure since data is less precise on fish. Anything that's not at that density would a rounding error at most. The densities of farmed fish are truly insane - usually far above the already high densities you see for land animals. The high level of concentration is not only terrible for the fish themselves, but also leads to huge pollution. Putting an unnaturally high count of fish in one area heavily concentrates their output
Parasite and disease rates are also super high. High usage of antibiotics in fish farming also lead to stuff like antibiotic resistance
I could keep going, but instead I'll just show some photos of the absurd densities:
what about crabs?
There's not really much crab farming in the US in general. It's basically all wild caught which has it's own negatives to the environment like overfishing. It's more of a thing in other parts of the world like South East Asia
Still at fairly high densities from what I can tell though not necessarily always as insane as the photos I showed earlier
Since you asked that made me actually reverse image search it to double check it was originally where I thought it was from. It was not, and now I am not sure where exactly it's originally from. The oldest version I found was from a blog from 2008, but on that post the file metadata says the photo was from May 11th, 2004