Depends on how and where it leaked.
My other half's uncles tank leaked while they were on holiday, all fish died and it did some pretty serious water damage to the house! They refilled the tank outside, it didn't leak, no obvious leak, remained a mystery!
If it was the seals, you can reseal a tank. Cracks in the glass aren't best fixed, instead you can replace the whole pane of glass. Although, it probably would be less of headache to buy a new tank! Depends on your enthusiasm for DIY!