People don't realize that firemouth cichlids are so diverse not only in coloration but also in body shape where they come from. I honestly do not think you are doing anything inherently wrong you just happen to have a "dull firemouth". I wouldn't fret though I have seen worse. Meeki have been inbred so much that sometimes you just get a fish with bad genes. What's funny is I can find f1 lyonsi(a fish which is endangered in the wild) easier than I can find f1 meeki. Jeff Rapps had some one his list years ago from rio subin but I have not seen any sense.
Here are pics of the rio subin variety I found online.

Honestly your fish does not look that dull to me...

Here are pics of the rio subin variety I found online.

Honestly your fish does not look that dull to me...
