Yeah, blue tangs grow even larger than yellow tangs. I know how tempting it is to get a tiny fish that's not even an inch and keep it for a while, but that's not an ideal environment. Yes there are people who keep tangs in 30s, 40s, 55, etc and will say "oh they're fine in our little tank, healthy and doesn't grow too fast", but what's best is to have a larger tank. Like I wouldn't recommend someone keeping an emperor angelfish in a 90 or 125 gallon tank, but people do anyway...Lol, my family always wants me to get a pretty colorful fish, and my reply most of the time is "sure if you want all my other fish/coral to get eaten". They have even tried to convince me to get a tang or some fish that will grow large to keep for a little while in my 70 gallon reef, but I don't feel like putting stress on a fish acclimating it to my tank, only to have it be more stressed when it grows too large and needs to go.
“Success is walking from failure to failure with no loss of enthusiasm.”
- Winston Churchill