These are are under my care for about the last 5 years, and I believe my sister had them for around 4 years. She had purchased them both very small and grew them out......however both have survived struggles although the blue tang had it the worst. They've gone through a a few tank crashes with my sister, however the Blue Hippo was stung by a Hadonni Carpet which is nearly always fatal even if they get away.
The story goes like this:
I finally talk my sister out of her beloved Blue Hippo tank as they are now downsizing, and they bring him down, poor fish scared as heck after a hour long car ride in a bucket. After a careful acclimation it's time for him to go in, and not wanting to net him I pick him up in my hands. At the time I had a 24" Purple Hadonni Carpet in my tank, which I figured the fish knew enough to stay away from. The carpet was on the right, so I left the BHT go on the far left of the tank. I gently lay him in the water and he ever so gently swims out of my hands, staying at the top of the tank and ever so slowly moving to the right. I figured we're good to go, but that's why he see's a crevice he would rather be in right next to the Hadonni and he dart for it. It's lucky it was moving so fast otherwise the carpet would have had him for lunch.....but he definitely got stung on the belly as there were tentacles hanging off of him. The BHT disappeared into the rocks for a little over a week, finally emerging skinny and hungry......luckily making a strong comeback. The Yellow Tang is the bully in the tank with the BHT mimicking him and bullying everyone else as well. So....he's been around 9 years, has gone through tank crashes, ich, and even a nasty sting and he's still kicking strong. I don't he's going anywhere for a while.