What to get next?

[neven]

well a while back to battle nitrates, i barely fed my tank and that in combination with having a lyretail anthias pretty much starved all my fish except the six line wrasse and tail spot blenny (foraged their food).

So i restocked a couple fishies last week, and im noticing the diadem dottyback is being really aggressive to the six line and i expected it to be the opposite way around. Not stressing the wrasse out enough to be a concern yet, since he buddies up with the tailspot, but still makes me wonder what would be the best new additions down the road.

My system is a 33G Display with a 33G sump, mostly a softie reef

Currently stocked with:
firefish
six line wrasse
tail spot blenny
diadem dotty back

my wife wants pretty colourful fish mostly in the tank, but i worry about conspecifics with my stock (or should i worry?). Unfortunately it'll likely need to be aggressive enough to hold up to the dotty back.

I'll be waiting atleast a few weeks before new stock, currently still sitting at 0 nitrates and near 0 phosphates. Corals are all doing great, and water change 10G / week.