On the other hand, if you still want to go for a marine-immitation, you are not limmited to african cichlids most of which are not community fish so don't mix them with peaceful species obviously).
You should take a look at rainbowfish:
http
/members.optushome.com.au/chelmon/ Even true marine fish don't surpass them in color by much. Don't be fulled by the dull color rainbows have when young or in the LFS - they'll brighten up soon after. Then there's all those cultivated livebearer strains that we perhaps often over-look as being too 'common'. If you use them tactfuly, you can get a lovely effect - swordtails, mollies, platies - they're all great for this sort of thing (plus mollies can actualy be marine

). Then there's all sorts of freshwater gobies and gudgeons - take the purple spotted gudgeon for instance - which look very much like marine fish in every way (except they don't need salt). If you can get large filter-feeding shrimp to add to the set-up, that'll give a more marine-like feel:
http
/www.petshrimp.com/index.html Just make sure nothing in the tank will eat the shrimp. Similarly, apple snails and other fancy freshwater snails will also make the tank feel a bit more like saltwater. There are many varieties and colors to choose from with snails - many, many more than you might think:
http
/www.snailshop.co.uk/index.html - just make sure you don't have a loach or something that'll make a snack of them! I can't help mentioning gouramies as well - the various colisa species, in particular, as well as the paradisefish and, of course, bettas, are very brightly colored and strikingly marked. They are fish to consider. As are sharks. With these last two suggestions, however, be very careful when mixing them all as all these fish have the potential to be rather aggressive.
Lastly, discus - the most obvious option - rival many marines in color. They are not all that difficult to keep if you do your research and, perhaps, are the perfect stepping-stone towards going marine.