P. flavivertex is a commonly bred Red Sea pseudochromis species. They're pretty aggressive dottybacks - on par with a bicolour (Pseudochromis paccagnellae) or Arabian (Pseudochromis aldabraensis). They are reef-safe, though they may consume small shrimp. As with any pseudo, they are best kept in an aquarium without dwarf angels, Pseudocheilinus sp. wrasses, or small rock-dwelling basslets. They reach approximately three inches in length.
The sunset basslet (Liopropoma aurora) isn't terribly rare in the wholesale trade, but not the most common either. The picture shown is probably Liopropoma aurora, but that colouring is somewhat off. A Hawaiian endemic that reaches six to seven inches in length, it's also a deeper-water fish (commonly found at depths of 100-150 feet). As such, they prefer a dimly lit aquarium. They are an interesting fish for a nano-tank when small, but outgrow it (and their colouration fades as they do) quickly. You will very rarely see this fish in a typical reef tank - the bright lights and active fish will keep it to the rockwork.