How to Choose Marine Aquarium Size

The right marine aquarium size should be chosen by taking into account the size of the fish, whether it is tropical or cold water, and the amount of surface area within the tank. Greater surface area provides more oxygen, which is highly important to the living things in the tank. Keep in mind the shape of the tank when considering this equation.

• Calculate the size of the marine aquarium you need not by the number of gallons of water it holds, but rather by the surface area. Fish need oxygen to stay alive, just like humans do. Fish consume oxygen from the water and release carbon dioxide back into it. Therefore, the oxygen in the water continually needs to be replenished through the surface area of the water. 


• Use the guideline or 24 square inches of surface area for every inch of an adult fish. Do not include the tail of the fish in this calculation. Following this formula will allow optimum oxygen levels, resulting in optimum health for your fish. This formula applies to tropical fish. Fish that live in cold water, like goldfish, require 30 square inches of surface area for every 1 inch of their body length, minus the length of the tail.


• Consider how the shape of the marine aquarium could effect this. Two different aquariums may hold the same amount of water but have different amounts of surface area due to the shape. For instance, rounded aquariums, like fish bowls, though may hold larger amounts of water, have less surface area because the shape gradually becomes narrower towards the top of the fishbowl.