Black patches

Julia

New Fish
Oct 22, 2002
2
0
0
#1
Does anyone know about black patches appearing around the mouth and face area of cichlids.  My haplachromis and fire mouths have both developed black spots/patches in the last week towards the front of their bodies, and the Firemouths have blackened mouths too.  The black patches look like staining, rather than being raised up or mucus covered.   Otherwise they seem very healthy, and their behaviour is normal.

The tank is quite large as I am strongly against overcrowding.
I've not introduced anything new into the tank for at least 6 months, have checked all obvious things - ammonia, nitrate, PH etc etc.  

Any ideas?
Julia *twirlysmiley*