Penguin tetras? I mean they might be slightly plumper than neons, but they are by no means tall.Pretty sure you'd be alright with the pandas and penguins, at least for a long, long time.
Most of the spiny "eels" (they're actually a type of modified minnow) will go after small fish like neon tetras - not necessarily chunkier small fish. I think it's more about shape than size - a Rasbora Heteromorpha at 2" will be much larger and harder to swallow than your average neon tetra, just due to body shape. The fish you're listing are pretty tall, robust fish, so I wouldn't be worried.
Interesting. So I will get one, and see how it goes. Maybe I'll get it small so it can get used to the idea of the tetras as tank-mates and not food, and so I can feed it mostly frozen food over time so it does not see living things as food?He was around 11" at his max size while I had him. It was a peacock.
Straight up no. I keep otocinclus with one 7 inch half banded spiny eel and another like 3 inch half banded spiny eel. They only get around 8-9 inches at most and the only thing they’ve ever attacked was shrimp. I’m sure fish fry would get eaten too. But I’d say at least a 1-1.5 inch+ fish would be left alone.