Tropical Freshwater and Coldwater Fish
Tropical Fresh water and coldwater fish need to be stocked I different ratios because different fish have different oxygen requirements.
Cold water can hold more dissolved oxygen than warm water and the inhabitants of tropical and cold water have adapted to this. Warm water also effects a fishes metabolic rate and so a goldfish placed in warm water would breathe faster and need more dissolved oxygen in the water.
Tropical freshwater fish can be stocked in a ratio of 2.5cm to every 30 sq cm of tak surface area. The standard ength of a fish is taken from the tip of its nose to the base of the tail. So a tank 60cm long and 30cm wide has a surface area of 1,800 sq cm. When divided by 30 cm the tank will hold 60 cm of fish whch equates to 15 small fish when fully grown.
To calculate Coldwater if you take the same surface area and divide it by 60 the tank can hold 30 cm of fish.
These are only guidelines.
Another thing to take into account is that Goldfish have very round large volume bodies which gives a much larger mass, and this needs to be taken into consideration when planning you tank.
These are only guidelines.
Another thing to take into account is that Goldfish have very round large volume bodies which gives a much larger mass, and this needs to be taken into consideration when planning you tank.