Macscale
Aquarium Advice Addict
A tang isn't going to be stressed out by a powerhead being added. There not being any water movement created a low oxygen environment with CO2 buildup along with a tang being too big of a fish for a 75 gallon tank is what lead to the death.
I'm going to have too +1. With sniper. All the reasons are correct and make sense perfectly.
Also, I never count the return pump in with flow. It doesn't really do much compared to Powerheads and such.
You didn't have any Powerheads in the tank besides the return?