I have several things I have seen...
Rich:
1( They buy bigger tanks
2( They buy “better” tanks. (Tank brands like FLUVAL)
3( They buy expensive substrate
4( They buy expensive fish
5( They brag
“Poor”:
1( They buy sensible equipment
2( They care more for their fish*
3( They essentially do everything opposite of what I said above.
* My pint of view, is that rich people don’t care about their fish. If some of their fish die, what do they care? They just go buy more. “Poor” aquarium owners tend to care more about their fish.
This is just my experience.