Like all fish, goldfish do not like to be petted. In fact, touching a goldfish can endanger its health, because it can cause the protective slime coat to be damaged or removed, exposing the fish's skin to infection from bacteria or water-borne parasites.
Goldfish tank size calculations. Its not uncommon to see 100 litres, or thereabouts, quoted as the minimum for one goldfish, with varying amounts of additional litres for additional fish.

Whats the best goldfish tank size? What aquarium is big enough. You should also get a descent quality filter.

Theres more to the goldfish tank size question, like what can happen if the tank is too small, can you put different goldfish species together in one tank, and how do you keep their tank water clean?

This particular example perfectly highlights why Goldfish Tank Size For High Water Volume is so captivating.
Goldfish Tank Size Formula. A simple starting estimate for fancy goldfish is to give the first fish a base amount of water, then add extra volume for each additional fish. The calculator uses this rule-of-thumb
Your goldfish tank maintenance schedule is directly tied to your tank size. In a 20-gallon tank, you might compulsion to accomplish two water changes a week to keep nitrates low.
The minimum tank size for fancy goldfish varieties is at least 20 Gallons or about 75 liters, anything smaller could lead to unstable water conditions unless the water is changed daily.