I have been looking at a Tomini Tang, and I noticed that they only get to be about 5". That seems very small for a tang. I also read that they don't need as nuch swimming room as other tangs. What do you think about one in a 65 gallon (36x18x24)?
I only somewhat agree with Andrew. In general, I would recommend a 4ft tank, but under this specimen, you might be able to get away with it with very select livestock. It would need to be about the only thing in there
As someone who's owned a tomini for years I could say for a fact they grow larger than 5 inches... they do stay small, but mine has stopped growing now at about 7 inches or is growing very slowly... I got him at only a couple of inches back when almost everyone was saying "what's a tomini?"... I remember seeing them around 15 years ago as butterscotch tangs... what a great fish
I originally had him in a 65... the same dimensions as your system... but knew he'd be going to a large system when our house was built. Personally, I see no issues with keeping small Ctenochaetus and Zebrasoma genus tangs in smaller system if you have somewhere to move them after they grow... Most Acanthurus species need ROOM even when small... could go off on tangents here, but long term I wouldn't keep any tang in a 65, but if small they'll be good for a few years... In the past I've kept small Zebrasoma in small frag tanks for algae control, handing them on to other reefers or keeping them now in my large system (my purple was just out of the larval stage practically!)
Here's my 65 from a couple of years ago (TOTM here at RC in September '04 )... you could see the tomini in the bottom right...
Here's some shots at feeding time of my large system after the move with many other tangs... these pics are nearly a year old and all of the fish have grown snce at different rates, with the tomini now around 7 inches... The last shot is under actinics only with flash and you could see the tomini feeding directly from the turkey baster...