try looking up either blind cave fish, or mexican tetras. their a cool looking fish with no eyes at all. even in moderatly decorated tanks, they are able to not bump into things or each other, and find their food rather easily.
i had several in a 10g tank, and they were awesome to watch. my son had even gone and netted one without me knowing and tossed it into my goldfish tank, where he seemed to happily live for close to a year before being wiped out by ich.