Cichlid selection advice

[BluEyes]

I've got a 15g tank that is currently only about 2/3 stocked, and looking for something to 'fill out' the stocking.

The specs are:

1 bloodfin tetra (survivor of 5 others he nipped to death, seems fine as a loner)
2 banded loaches
1 clown pl*co
1 spotted croaking catfish (like a raphael cat - very spiny, very secretive)

Water is from a well, so alkaline and hard (but not super-hard, exact specs vary be season, rainfall...
Aquaclear 150 filter
26W CF lighting
fully planted with crypts, anubias, wisteria, and dwarf sagitaria
some rocks, and a piece of driftwood in one corner

The bottom strata is plenty full as is, so I was thinking a middle/top dwelling cichlid or two (not nessacarily the same species - don't especially want to breed).
Looking for an African preferrably. Something that wouldn't get much past 3", or at least not for awhile (hoping to convince g/f that a 20L would look better there) and isn't TOO combative.
Also, something not too uncommon - there aren't that many fish shops around here...

[Jayhawk]

Cichlids tend to prefer the bottom/middle strata of the tank, so I'm having a hard time figuring out what would work, especially with a limited number of fish stores (and I'm guessing a non-exotic species selection).

First off, your tank is pretty heavily stocked. The smaller fish (SA dwarfs less than 3" and Tanganyikan Cichlids of which many are smaller than 3") all prefer the bottom of the tank. Also, most SA dwarf cichlids prefer soft, acidic water.

However, here are some suggestions (one fish only).

Apistogramma borelli
Apistogramma cauco (oh heck, it's the cockatoo apist - I can't spell the last name)
Nannacara anomala (golden eye dwarf cichlid)
Laetacara curviceps (flag cichlid)

Those above are SA and do OK with higher pH and hardness.

From Tanganyka (single fish only):
J. transcriptus (dwarf julie)
Neolamprologus caudopunctatus

Perhaps a single Krib (west african).