Filters will not remove, or lessen Nitrates. The beneficial bacteria takes Ammonia -> Nitrite -> Nitrate and it stops there.
A heavily planted tank with lots of floating and fast growing plants can keep Nitrates lower than normal because the plants will use Ammonia as their nitrogen source, they'll use it before the bacteria can.
However, weekly water changes are still required. There are a lot of wastes in a closed system that the filters do nothing to remove (urine, pheromones, etc) so the only way to remove them is through water changes.
Freshwater community fish are typically not all that colorful when compared to marine and cichlid fish. A lot are silver with black, some with reds, a few yellows, a few with blue. Check your local stores, they might have more rare varieties. Neon Tetras are probably one of the most colorful community fish I have seen, but they are small so all your other fish must be small too.
Key will be knowing your water pH, GH, and KH. That will dictate what kind of fish you can have.