Is there a difference between the 6 and 7 stripe?
Yes.
There are many variants of frontosa's with most possessing 6 stripes.
The Kigoma is the best known and perhaps most available 7-stripe variant (the Boulomboro and Bangwe being the other two 7-stripers).
The first 'stripe' of these 7-stripe variants is actually more of a large 'patch' which occupies the entire facial area below their eyes down to the mouth and bottom of the gill plates.
This is significantly different than the 'masks' extending across the face that the southern 6 stripe variants have or vertical eye bars that the northern 6-stripe variants have. The 7-stripe variants are also a litte more long-bodied than the 6-stripe variants.
Kigoma variant (7-stripe frontosa):
Example of the difference between the 6-stripe burundi variant's vertical eye-stripe and the 7-stripe variant's patch: (one burundi at upper left, the other two are kigoma's):
With that said, not all frontosa's with 7-stripes are kigoma's, boulomboro or bangwe. Cross-variant 'hybrids' for example can possess 7 stripes.
Most of these cross-variants are usually kigoma x burundi and resemble burundi's with an extra stripe (that is to say the first stripe is a vertical burundi-like eye bar rather than kigoma's 'patch').
The 7-stripe frontosa you're inquiring about is most likely a burundi x kigoma cross-variant.
