I'll share my experience with these, as they are far and away my favourite small anthias.
Basically IME they are comparatively easy to keep in a narrow range of tank conditions. And that's the hard part, since as hobbyists we get greedy and are tempted to "˜push the boundaries'...:thumbsup:
Low to moderate temperatures 22-24C; no other planktivores that chase or bully them and small regular feeds throughout the day. With this in mind their tank was a 3 x2 shallow, and housed a pair of colins angels, wetmorella, helfrichi firefish and several similar innocuous species. One loss initially, a harem survived almost three years.
So what went wrong? Well, I wanted to add other anthia species. The harem of P. cf aurulentus shattered tank harmony. The ventralis hid and some stopped coming out to feed altogether. When they did, the alpha female soon put them back in their place. Within a short space of time most had perished.
I don't think a dedicated tank is the only way to keep them, but feel it's most likely to be successful long term. As an aside, I have only kept the local ones from the coral sea, and some from Vanuatu. The latter grew larger, and actually bickered with the locals. If you have a choice mid to large females would be the best buy. Males transition very fast, and a true WC alpha male is worth avoiding IME. They find it hard to adapt, but juveniles don't.
Hope that helps.
Angie