* Goldfish grow: Goldfish, especially common goldfish, can grow significantly larger than 1.5 inches. They can reach 10-12 inches or more, depending on the species and conditions.
* Waste production: Goldfish produce a lot of waste compared to other fish. Overstocking a tank leads to poor water quality, making the fish sick.
* Individual variation: Even fish of the same species and size can have different metabolic rates and waste production.
* Aquascaping and filtration: The number of fish you can keep also depends on how much space is taken up by decorations and the efficiency of your filtration system.
A general guideline is to aim for 1 inch of fish per gallon of water. This means a 55-gallon tank could theoretically hold 55 1-inch fish. However, considering goldfish growth and waste production, it's much safer to start with fewer fish.
Here's a more realistic suggestion:
* Start with 2-3 goldfish: This gives them plenty of space to grow and reduces the risk of overstocking.
* Monitor their growth: As they grow, you may need to reduce the number of fish or upgrade to a larger tank.
Remember, it's always better to err on the side of caution and understock your tank. This ensures a healthy and enjoyable environment for your goldfish.