Actually, XB and HBRTG are the same. They're all the production of crossing Malaysian Gold, which is extinct, to RTG. That's why they all have red in their tail. 10-15 years ago, there's no such thing as XB, or HBRTG. It's either Malaysian Gold (also called Super Gold) or RTGChaitika;3090352; said:My understanding is that HBRTG is a cross between xb and RTG. If the fish got more of the xb genes, it's possible to still cross, but it won't be anywhere near the same intensity as an xb. My RTG is showing colour in the 6th level now. Who knows what could happen in a couple of years?