it will be ok now, but as it grows will need a larger tank, but if you want a fish that will get bigger very quickly you really shouldnt get one with the problem of having to move it down the track, as achillis is a very sensitive and fragile fish, even the most experiencet aquarist have trouble with them and will stress the fish out when moving it, the internet does say a minimum of 100 gallons but imo its still to small for a medium to larger surgeon, maby go for a kole, they are nice