Okay when that fish store still has that pleco all nice and healthy 15 years later let us know. Same with Oscars. Those fish all live long lives if kept properly. But as was mentioned they will all end up with problems due to water quality issues.
And up above it was mentioned a 2 ft snake head kept in a tank 1.5 ft wide. Well that sounds fair and resonable doesn't it. I bet that fish loved his home.
Do any of thoese cramped fish live like they do in the wild? Do they swim fast, stock prey in such appalling conditions? I doubt it. And oscar should be full of personality, exploring, looking for food, hunting, but more likely they are just sort of hanging out and doing nothing except growing some good old HITH.