I'v seen the advert my self, "sungguer" is one of the many Melanotaenia still awaiting a proper classification. As a genus of fish melanotaenia is a complex and at times a difficult group of fish to identify correctly, there are many fish being sold here in the uk and elsewhere as a specific species that are infact hybrids so, unless you know the source of the fish or are buying from a trusted private breeder it's very easy to end up with a hybrid fish, i would be asking for details of where the fish being offered originated from.The other issue is that at 5cm the fish being offered will probably be very difficult to sex correctly and as we know it's the male fish that are spectacular with the females mostly being very plain looking fish, or boring as i like to call them😳, cheers ,Alex