Were the fish being fed when taking that video? Couldn't tell if the particles in the water were food or just particles...
They looked pretty anxious and stressed, to be honest. They were all circling around each other in the same spot... Were they eating, or is that how they normally are?
I wouldn't imagine that you would have aggression problems, because with so many Tangs in a "small" space (at least compared to how many Tangs you have and how large they are) they simply
can't form a "pecking order." Too much confusion.
I hope I'm not coming off as part of the notorious "Tang Police" as I don't have a Tang, and won't have one until I have a tank large enough, but IMHO, that is too many Tangs for the tank. I can't fathom putting 18 Tangs in a tank that small, but I digress.
They
are gorgeous, and I'm sure the tank meets your satisfication standards...
And for the record, Achilles Tangs do not seem to be as "fragile" as they're noted to be; at least not any that I have observed.
For example, the office my fiancee works at has a 75 gallon tank with a Yellow Tang, Achilles Tang, Spotted Grouper, Blue-Jaw Trigger, Fire Clown and Blue Devil Damsel. They've had those fish for over a year and a half with no water changes, hardly ever checking parameters, etc. and those fish get fatter and larger every week... Maybe they're just lucky?
Anyway, have a great day!
