Contrary to popular belief…goldfish DO NOT belong in a bowl. It is extremely difficult, even for the advanced hobbyist, and basically impossible, for a new hobbyist to properly care for a goldfish in a fishbowl. Goldfish are messy fish; they produce an inordinate amount of waste compared to other species of fish. Moreover, goldfish will grow to anywhere from 6 inches to 12+ inches (depending on the breed). As a result, you’ll need a decent size tank to be able to maintain adequate water quality and proper care for your goldfish. A good rule of thumb to use is 10 US gallons per goldfish (8.33 Imperial gallons or 37.9 litres).

Before looking for a fish tank, consider and measure out the area where the tank will be situated, preferably away from windows or direct sunlight, as this will stimulate algae growth… unless you want to spend all your weekends scrubbing the sides of your tank.

What size tank should you buy? Well, with most hobbies, it is wise to start small..."test the waters", if you will, and upgrade once you are more confident/invested in the hobby. However, with the world of aquaria, it's the complete opposite. It's wise to buy as big a tank as you can afford (within reason of course). As large tanks allow more room for error and surprisingly don't require much more effort to maintain than a small tank (in some cases, even less effort). Often is the case that novice aquariasts start out with an inadequate setup and not too surprisingly lose their fish to diseases stemming from overcrowding and poor water quality. With such disheartening early experiences, it isn't a wonder that they would abandon the hobby, concluding that it is too hard...too much work...or just not for them.

Personally, I think that the best size tank for a beginning hobbyist is a 20 or 30 gallon tank. The bigger the tank the better. With a larger tank, you won’t expose your fish to sudden dramatic swings in either temperature or water quality as the effect is diluted over a larger volume. With a smaller tank like a 10 gallon, a filter turning off due to power outage or even a window left open overnight can cause extreme change in water conditions that may spell doom for your fish… making for a very rude awakening.

All else being equal, shallow and longer tanks are preferable to taller tanks. Shallow tanks have larger surface areas which allows for more oxygen exchange (oxygen exchange only occurs at the surface of the water, so the greater the surface area, the more aerated the tank). Shallow tanks are also easier to maintain as it is easier to reach the bottom for vacuuming, cleaning the walls, rearranging the décor, etc… And lastly, with longer tanks, there is more viewing area to admire your beautiful fish and aquascaping.

To find out how big your tank is and other vital statistics about your aquarium, try our tank volume calculator.