What is the submission look like? My smaller blue chest compressed his fins and swim sideways a little (body horizontal, actually about 45 degree, to sand instead of vertical). Is that submission?
That's roughly how it looks like, though the compressed fins for itself can also be the precursor to aggression or an attack.
For the submission pose they get their body in somewhat of an "S" shape while tilted sidewise and in front of the dominant, usually exposing their side.
From above it looks like they try to form an italic "T".
When it gets further towards bonding and spawning the female may also do something similar to the sidewise shaking you see with clownfish.
I've seen that all with dwarf angels (C. argi, C. bicolor, C. bispinosa).
How can you tell which is a male and which is a female? lol
The little ones are all still females, but the larger one will eventually become the male.
I would say everything that comes in below 5 to 6 inch is still female.
Mature males have massive gill thorns, usually twice as long as those of females of equal size. This is usually the easiest way to tell male and female apart.
Under aquarium conditions they may mature at a smaller size, but the gill thorn difference between male and female should always develop.