One of the bigger reasons has to do with the square cube law - as the size of something increases, surface area increases by a factor of 2 but mass increases by a factor of 3, so little fishes have a surface area-to-mass ratio that is quite a bit higher than a larger fish, and they’re more susceptible to abrupt changes in temperature.
Kinda like how an ice cube will melt a lot faster than a big slab of ice, the core temperature of some small fish like a goldfish is gonna change more rapidly than the core temperature of a big fish like a trout so they tend to be a lot more finnicky in regard to significant and instantaneous changes to temperature and stuff. A larger fish might shrug off a significant change because it affects them more slowly, but that might be a totally wild an overwhelming experience for a little fish to go through
And in a similar but completely different way, the fish are being added to massive bodies of water. Home aquariums are minute in comparison, so they can’t balance out chemical swings as easily and are much more prone to higher levels of nitrites and other toxic chemicals. The larger the body of water, the more stable the water quality.
You could probably air drop one goldfish into a 100 gallon tank and it’d be fine (assuming it survived the fall).
something i love about Lemmy is that on the drop of a hat someone is willing to calculate the “surface area to fish ratio”
Problem is, you almost never know if that’s actually true or complete bullshit.
It seems plausible, but killing virgins for rain also seemed plausible back then in the 70s.
The math actually works, and is quite simple. Just assume the fish is a sphere
I’m confused though. Don’t people use this to talk about how small things like bugs can fall from a large height and be uninjured, but large things like a human or elephant will be injured if falling from a height? I feel like what you’re saying is backwards to what the internet has told me.
No, it’s all the same in that regard - a ladybug will have a far higher surface area to volume/mass, and that affects terminal velocity.
Ladybug might have 10 square millimeters and weigh .05 grams, 200 square millimeters per gram
Elephant might have 15 square meters and weigh 5000 kilograms. 15 million square millimeters and 5 million grams, so 3 square millimeters per gram
But the elephant in the room (slaps knee) is momentum.
Let’s say, hypothetically, we shove a ladybug and an elephant off a 125m cliff and pretend they both have a ridiculously high terminal velocity. That’s enough for them to reach 50 meters per second or 180kph. .05 gram ladybug’s momentum would be an infinitessimally small 2.5 kg·m/s, meanwhile the elephant is at 250000 kg·m/s, and the elephant explodes.
The thing that makes the ladybug survive the fall (ridiculously low mass relative to surface area) is the same thing that would make a ladybug freeze in minutes if you tossed it in a freezer. Conversely, elephant wouldn’t really be bothered by a couple minutes in a freezer.
It’s that rapid change in internal body temperature that stresses smaller fish out, dumping them in water that is much colder or warmer than them
