When purchasing a goldfish tank, the first consideration should be the number of gold fish you plan to house in it.

In order to ensure the oxygen in the water is aequate to support all the gold fish, the surface area must be as large as possible, as compared to the amount of water in the tank.

For example, 2 containers might hold the same amount of water, but the surface of the water exposed to air can vary greatly between the two goldfish tanks.

Goldfish tank specifications

Gold fish are special because they need a lot of space. They are messy, & tend to grow quickly and also need steady water flow conditions. Pick a bigger tank if you can afford it, or else plan to upgrade when your gold fish grow in size.

To work out the capacity of a rectangular goldfish tank in gallons, multiply the length of the tank by the height, and then by the breadth.

This gives you the volume of the goldfish tank in cubic inches. You can convert this to cubic feet by dividing the answer by 1728, and then multiplying the result with 6.25

Take for example a goldfish tank that is 36 inches x 12 inches x 12 inches in dimension. The volume will be 3 cubic feet. When applying the calculation above, the capacity of this gold fish tank is 18.75 gallons.

The figure that is of more importance when you breed goldfish is the area of the water surface. This can be calculated by multiplying the length of the goldfish tank by the breadth.

We should allow for 1 inch of gold fish (not including the tail) for every 24 square inches of area. In the example we just used earlier, the surface area of the gold fish tank would be 432 square inches. Divide this number by 24, and you get 18. This is the maximum number of goldfish you can put in this gold fish tank.

It does not matter how the inches are distributed, as long as they add up to 18. As the fish grow, they must be thinned out to maintain the original 18 inches.

Testing a goldfish tank for leaks

Before setting up a gold fish tank, it is advisable that you check it for leaks.

Keep the goldfish tank on a flat, solid surface. Fill it up with water. Leave it there for many hours. Then, look at the table-top for evidence of leaks, such as puddles of water on the table.

If a leak occurs, it may be repaired using sealants. Most modern glass goldfish tanks have already been sealed by one of these compounds, and the chance of a leak are really very small.