Q. What about how many fish per gallon rules such "one inch per gallon" or "one centimeter per two litres?"
For starters, the one inch per gallon rule (or 1cm per 2L) only works for tropical freshwater fish; cold and marine fish need more space. Also, tanks are often not filled to capacity; space at the top and displacement by decorations and gravel varies from tank to tank. Nor does it account for the shape of the tank (a consideration as non-standard shapes become popular) or the needs of specific fish species. However, for standard-shaped tropical freshwater aquariums, the one-inch-per-gallon rule gives a similar result as the surface area rule. Regardless of the rule, the adult fish size and body type still needs to be considered--not the juvenile sizes most commonly sold in fish stores.
Aquarium Tank Size | Length, Width And Height
A fish tank of proper size is one of the very first requirements for setting up an aquarium correctly. Its importance is often overlooked. Undersized fish tanks can cause many problems including but not limited to: Unstable water perimeters; quicker build-up of harmful chemicals; lack of enough oxygen; hard to keep clean; and not enough swimming room for the fish. Most of these problems can lead to the death of fish.
View a directory of tanks by size sorted by tank size.
You will need some sort of stand on which to place your tank. Thestand can either be specially designed to hold your tank, or existingfurniture. The first thing to consider is whether your chosen standcan support the tank's weight. When full of water, tanks weigh aLOT (the water alone weighs roughly 10 lbs/gallon). ConsultXXX for detailed specs on common aquarium sizes.
How Much Do I Need? - Aquarium Equipment Sizes - The Spruce