Round Bowl

What is the difference between a tank (flat-back tanks) in a round tank? ?
Is it better to have a goldfish in a tank or a face flat tank round? Will it affect your health or something? What if you have a filter in the receiver, rounded the difference?
Aquariums are be 1 gallon or smaller. This is enough space for a fish of any kind. Aquariums are usually larger – 2 1 / 2 liters or more. A goldfish A minimum of 29-30 liters, with the addition of 10 gallons for each additional goldfish. We also require a good quality filter – preferably one made by the twice the size of tank you have. For example, 1 goldfish a 20 gallon tank with a filter made for a 40 gallon tank.