Aquarium size is one of the first things you should consider when planning a fish tank for your home or office.
Type of Fish Tank
The shape and type of your aquarium can affect the number of fish that you can put inside it. If you have a regular-sized rectangular fish tank—the most common type—you can put in up to 2 average-sized fish per gallon. For those interested in small fishes, your rectangular tank can accommodate 3 or 4 fish per gallon. However, you need to reduce the number of fish per gallon if your tank is hexagonal or somewhat vertical in shape.
Filtration is important in promoting the health of your fishes. If your tank is equipped with bio-filtration and other mechanical gadgets that aid in cleaning the water of harmful elements, your regular aquarium can accommodate 1 or 2 additional fish.
Type of Fish
The number of fish that your tank can accommodate depends on the species that you are planning to have. If the fish is long and wide, then you should only put 1 in an average-sized fish tank. If you own a goldfish—which can grow according to their living space—you must settle for 1 fish per 10 gallons of water.