Proper size for tangs?

[whatcaneyedo]

The powder blue bullies the purple tang in my 225gal. The first few weeks were really rough and the purple would swim laps constantly, always going in the same direction and rubbing one of sides against the glass until it started to chafe. In the years that have followed they have calmed down but the powder blue still 'charges' or takes swipes at the purple from time to time. The powder blue is also a stress-case and temporarily outbreaks with a little bit of ich each time I add a new fish. This has been going on for a decade. Both tangs were medium size when I got them from well established friend's tanks that had shut down. Given this experience I wouldn't add a third to my system.

[DorySaid]

Ideally, I would say 180 or larger. I've had tangs in a 90 gallon before. But when it comes to longevity and overall health, I think you'd be better off with the biggest tank you can afford/accommodate. Also I wouldn't recommend stocking the hell out of it with live rock and corals to allow the extra swimming room that you intended by setting up such a big system.

[gregzz4]

Shark

Keep in mind tank size doesn't always equate length, or needed swimming space.
Rectangular tanks are best for Tangs if you are thinking about volume and smaller tanks.
A 3' 150g sounds huge, but a 4' 75g is better for swimming laps.
Tangs like to do 'bursts'. So the longer the tank the better.

For a Yellow tang I'd recommend at least a 4' tank for a juvi. Mine is reaching 4" and will need to be re-homed in a couple years, or sooner. Right now he's OK in my 4' 75g and I don't yet see any issues with him pacing. I hope to keep him for awhile longer, but with tangs and smaller tanks you need to consider their health as they grow. Once he starts pacing I'll be forced to re-home him.
Mine is already nearing my tank size. I watch him lapping the tank, that is to say he's nearly swimming from one end to the other in 'bursts'. Once I see he's running out of room it'll be time for a move.

So, the bigger the Tang, the longer your tank should be. Big tank volume is great, but a 'square box' is not best if you are size restricted. Ya?

Powder Blue tang 9" growth size. Holy crap thats huge for a 150g 4' tank. It'll be cramped for swimming space - probably get depressed and eventually die. Put it in an 8' tank and I'll bet you it's happy, or at least happier.

Use LiveAquaria online to get some quick stats on your fish picks, and over-estimate your requirements to be sure you have enough space.
Don't use their tank size recommendations as they are out of whack when it comes to tangs.
Keep the length longer with smaller tanks, or go big.

With all that said, Canreefers will tell you they've had success with smaller tanks and smaller fish. Sure, it's do-able. Just be prepared to deal with fighting, stress, and eventual re-homing.

Good luck with your new build. I hope you make it huge, or at least very long.

[gregzz4]

I want to add this ...

I saw a 2018 tank picture recently that appalled me.
A purple tang in a cube. A small cube. I could see how small the tank is based on an MP10 wet side in the photo.

Bad fish keeper ... shame on you

[WarDog]

🚓🚔🚔🚓

Here come the Tang Police!

[DKoKoMan]

Originally Posted by gregzz4

I want to add this ...

I saw a 2018 tank picture recently that appalled me.
A purple tang in a cube. A small cube. I could see how small the tank is based on an MP10 wet side in the photo.

Bad fish keeper ... shame on you

I agree. I think it’s ridiculous to restrict a fish that likes to swim laps in a cube.