The number of springer damselfish you can keep in a 180-gallon aquarium with around 10 fish already (surely you can count them? ) depends on various factors including the size of the damselfish, their behavior, and the overall compatibility of the fish in the tank.
Q: Which other fish do you have?
In a mixed community tank, it's important to consider the different species' behavior, compatibility, and potential aggression. Adding too many fish too quickly can lead to stress, aggression, and water quality issues.
Depends on what you're trying to accomplish. I have a single one in a 34 and it's a model citizen. Mine pretty much ignores the other fish which are gobies and clowns. The risk I would worry about is 1) them being territorial with each other 2) aggressive behavior if you end up with a spawning pair.
I've started to enjoy multiple Chalk Basslets over multiple Damsels; I recently put 3 into my 150 gallon, and at times they 'pal around' together in a tight group. I will probably get 3 or 4 more. Their blue hues tend to get more colorful as they they older.