I would not take altums in smaller than 700 litres and height should be 65cm or more. There guys get 35-40cm high over time. Well, those Peru altums dosnt. Real altums are quite rare in market cause nobody ever been able to breed them, so only wildcought are available.
I used to have four of these in 160x60x58=550 litres and that was way too small for adults. Now I have bigger tank but I havent seen real things in shops in quite a while.