Aquarium Dimensions and Volume Calculators

Dimensions

Below are the standard rectangular fish tanks made by Aqueon (formerly All Glass Aquariums) and Marineland (formerly Perfecto). I do not have a preference for either brand over the other, in my experience they both make high-quality, reliable aquariums.

Not all of the tanks listed below are available from both Aqueon and Marineland. Most come in multiple color options and most of the larger ones are available pre-drilled with built-in overflows (some overflows are built in to the corner, others are on the back).

This list includes the basic/standard rectangular tanks. This list does not include bow fronts, hexagons, cubes, columns, etc. I prefer the standard tanks below because you get more volume for your money. The special shapes cost a lot more per gallon. If you are interested in any of the other tank shapes, just ask your local shop what all they can get in for you.

For reef tanks, I highly recommend a tank at least 18″ wide (front to back). This gives you enough space to set up a stable rock pile as well as allow enough width inside the stand for a 12″ wide sump. This would also apply to tanks for African cichlids where you will also have a lot of rock work.

Note: Tank volumes are not exact. For example, the calculated volume may be 34 gallons but the tank may be listed as 30. There are two reasons for this. One, companies round the volume (75 makes more sense than 79). And two, the dimensions are the outer dimensions and the internal dimensions are slightly smaller. Don’t worry about getting it EXACT. The difference between 75 and 79 doesn’t change the heater you need, the filtration you need, etc. Even medication or salt dosing has wiggle room and it’s impossible to calculate the actual volume of water in a tank when you consider substrate, decorations, rocks, filters, etc. So don’t worry about it THAT much. If you have a 75, add 75 gallons’ worth of salt if needed, dose medications based on 75 gallons, etc.

In addition to the chart below, you can find more information at the following websites:

Aqueon

Marineland