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This aquarium calculator will help you convert between Imperial, metric and US units of measure. There are a couple of important points we would like to make first, about stocking levels and total weight.
One of the most important things to get right is knowing how many goldfish you can keep in order to reduce the risk of poor water quality (see Golden Rules for full advice on keeping healthy fish). It is the surface area (length x width) of an aquarium that determines stocking levels, as fish need a certain amount of surface area for enough oxygen to dissolve into the water.
As a guide (but see the notes below!), in a coldwater aquarium you should allow:
- 60 square cm for each 1 cm of fish body length excluding the tail
- 24 square inches for each 1 inch of fish body length excluding the tail.
For example, in a 60 x 30 cm (24 x 12 inch) tank you can keep a total of 30 cm (12 inches) of combined fish body length, such as three 10 cm-long fishes (three fish each 4 inches long), or two 15 cm-long fishes (two fish each 6 inches long).
- this rule-of-thumb assumes satisfactory filtration and aeration are provided;
- some authorities quote 30 square inches for each 1 inch of fish body length instead of 24 square inches;
- larger fish have a proportionally larger body mass than smaller fish and therefore proportionally larger oxygen needs (e.g. one goldfish 6 inches long has greater oxygen needs than 6 fish each 1 inch long).
You should therefore be conservative when deciding upon stocking levels - do not overcrowd your fish, or you will create water quality problems and fish health will suffer.
The weights given are the weight of water only. Please remember to add appropriate amounts for the dry aquarium, the hood, gravel & rocks, internal filtration and the stand in order to find the total weight of an aquarium (for example, when considering where to posttion it).
Surface area and number of fish calculation
Volume and weight calculation
If you do not have a rectangular aquaruim, we regret that this calculator will be of limited use; we may add further functionality in due course.
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