i think they are just young. i noticed some reddish orange developing on a few of them (these will likely turn out to be males), and all of them are smaller than the adult size.
i suppose its possible that they are hybrids of d. erythromicron and d. margaritatus, but definitely arent d. erythromicron (if that is the fish you meant). they have spots, not stripes.
Eheim Pimp #296
Canon Pimp #67