Yeah, I'm not sure how successful it would be though. Essentially the brownorum's iridescent layer is only in one area, on that spot, but splendens already have an iridescent layer which commonly covers large areas of the body and fins. If the brownorum spot pattern were only due to one gene then everything would work out pretty simple I imagine, but if not, you'd probably never get it to show up just right in the hybrid. Hybrids are often sterile too, so that would be another issue... you might not be able to line breed for what you want after that first cross. It'd be fun to try though, I think. Probably better to cross a non-iridescent splendens with the browonorum if you were to try it to see how the pattern came out, whether the splendens genes would spread the iridescent layer out like usual or whether it would stay in relatively the same area as on a brownorum. A solid red fish would probably work best.