Hello,
One point of contention is that tangs don’t “school”. They shoal. I don’t mean to split hairs, but it’s important to understand the difference.
https://www.oceandimensions.com/shoal-or-school/
Fish that school often “need” or feel most comfortable together. Shoaling can begin and end and is more what you see in tangs.
They often stick together to feed but if they could feed in each others absence they may even prefer that. Anyway, enough splitting hairs!
If you have enough “real estate” - this may work. Purple are more aggressive as zebrasoma go but with several I’m sure you’d be fine. In fact, even powder blues get along with one another in numbers great enough! I’ve had 6-7 together for a time but disease took it all but 2. 2 didn’t work. But I’ve seen this in large aquaria many times and I consider PBT particularly surly.
The small size is likely to make them less of a threat and less of a target to the incumbent tangs. However - it sounds like the sailfin is the true tank boss. He doesn’t allow aggression because he is top dog (I hope that never changes or you’ll end up with a likely “mad king” situation if you get the reference).
However, your sail is a zebrasoma tang as well so it’s possible he would not approve of this idea but I’m guessing numbers are your friend in this instance.
However - being so small, it also makes the new purples more susceptible to death by aggression as they will be quite fragile. As ruthless as it sounds - if you want 7, I’d buy 10. Law of averages and things happen. 2-3 isn’t likely to work so you’ll want to ensure you have room for loss.
My typical disclaimer though is that individual fish have individual temperaments and nothing is ever guaranteed - I try to operate (based on experience) on suggested probabilities!
If you do accomplish this, you must post videos! :)
