Alot of people i know say chiclids are very close to freshwater looking fish becuase they come in a lot of really pretty colors. I would like a chiclid only tank, but from what i hear, you can only have chiclids with chiclids and they require very specific conditions.
So... Clown loaches are very pretty and colorful with colors similar to the saltwater clown fish.
You can get bala sharks, iridescent sharks, and redtail sharks. The redtail shark and redtail loach are both really similar in color and very pretty, with dark chocolate bodies and red fins.
THey have freshwater puffers, but i don't know anything about them, or what you can keep with them
hmmm.. what else is pretty.. Dwarf Gouramis are VERY colorful, you can get Flame, Powder blue, and neon blue. I personallylike the flame gouramis to add some bright red to my tank. And they are labrynth fishes so than can get oxygen from the surface.
Theres a lot of really pretty freshwater fish, Discus are really expensive, and more work to keep, but really pretty. Just go to some of your
LFS and look around, im sure you will find some fish you like that are just as pretty as saltwater fish!