But putting two strange oscars together often results in the death of one, so keeping them in pairs is difficult. It is much better to raise the fish together from babyhood. If you want to be reasonably certain of getting a mating pair, you'll need about 6 oscars though, which means a big tank. A school of tinfoil barbs or other large barbs or large silver dollars are good as tank mates if you have enough room. The question is why would anyone still find them appealing given their anti-social tendencies.
Cichlid tanks benefit from plants as much as any other.
Just bury an eggcrate just below the surface of the gravel, and use a strongly rooted tough plant like anubius or valisneria. Putting the plants in terra-cotta pots is also a good idea. Once valisneria is well established, you can use silver dollars as tank mates since even though they are plant eaters they dont eat val as fast as it can grow. Do NOT do this. Ph stabilisers contain phosphates and should be avoided.