No, think of tempered glass being stronger by being denser. You start with a normal piece of glass and heat it up and then you let it cool down in a specific way to create a very high surface tension. In the process the glass will shrink thinner. You cannot cut it or drill it after it has been tempered. It is impossible to let the glass cool down perfect either, so it is unsuitable to be made into a mirror (the surface is wavy). For your aquarium you want the glass to be as smooth and even as possible so nothing gets distorted. Compared to non tempered glass it will scratch easier. It is also very easy to shatter the whole glass when a small heavy object hits it or falls on it. Tempered glass has its uses, but not for the sides of a fish tank.