Thats all they sell now unless its been grown out or something.. i watched a video on then catcjing blue tangs in the wild snd they capture them as babies and leave the adults alone so they can repopulate
I don't agree with the tangs needed to be larger. I have a 180g I have 2 yellow tangs which were 1.5' when I got them. A pacific blue tang which was 1". A banner which was about a half dollar size and a PBT who was the largest at around 3". He is the leader but they all get along. The yellows are about 4". The Pacific is about 6". The Banner is about 5". The PBT is about 6". I think the smaller adjust well and defiantly handle shipping better. They all went in at the same time. Which helps them all getting along. They are all fat and colorful.
I bought my tangs at 3" or less. Scopas, pyroferus, lieutenant, naso (& foxface). Original goal was to get them all at once (always very difficult, and it didn't happen), QT them, add them into DT together. I feel that getting them small helps to minimize aggression. I also like to watch them grow. It has taken 2.5 years for my naso to get to 7" but it's been really great to watch it grow. For some species, getting them small also means you can keep them longer (e.g., Vlamingi).