Personally I think you’d be best going for a group of all juveniles/young specimens. With 3-4 and 2-3 other fish I’d say 2’ cube minimum, 3’x2’x2’ best IMO. Others may say otherwise though.
As for how did they establish, well if this helps I have had my pink streak for 2 years and my possum was around for just under a year before the urchin decides to take a nice meal (I still hate that urchin to this day - It’s in my 4’ tank).
I’m gonna pour one out for your possum wrasse RIP. I’ll go with the 81 Gallon Fiji cube (35.3”x23.62”x22.44”) unless space in the new apartment says otherwise then the 60g cube (2’X2’x2’) THANKS YOU (I’m beyond indecisive)
BUT now idk what to stock. Taking your advice I’m thinking:
Option A:
-1 male juv. Wetmorella albofasciata
-2-3 female juv. Wetmorella albofasciata
-1 Prognathodes aculeatus (introduced last)
Option B:
- (Pair) 2 Wetmorella albofasciata
- 1 Prognathodes aculeatus
- 1 Plectranthias inermis
Option C:
-1 male juv. Wetmorella albofasciata
-2-3 female juv. Wetmorella albofasciata
-1 Plectranthias inermis (Introduced last)
Let me know which one smells like it would have the potential to thrive. A is my favorite, B has the most variety, and C is the most reef friendly. Not trying to overstock so let me know if I should just take out the Hawkfish or if I should forget having more than a pair of the white banded possum wrasse. Have to request the fish from the LFS (3-9 weeks to ship) so no rush.