Predator vs Protector:
Which protectors you keep in your tank to protect against which predators... What measures do you take to prevent infestation... What do you do to treat once infested...
Or maybe beneficial fish vs fish known to nip at zoas
Water conditions:
salinity, flow, pH swing, temperature
Light cycle and spectrum
DSB, SSB, BB and how mow much LR you keep in your tank
Filtration:
wetdry/ trickle filtration/ Undgergravel filter/ refugium/ skimmer/ Benthic zones