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How big of a tank do 3-4 bubble eye goldfish need to thrive?

Updated on September 23rd, 2025

What is the best sizes tank to get for 3to4 bubble eye goldfish? I haven’t brought them yet.

1 Answer

Most Helpful Answer

Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

Veterinarian

Published on May 19th, 2019

Hi, and thanks for your question.
There is a general rule about it which is a rough estimate not to overcrowd your aquarium and avoid excessive production of feces and organic debris.
The rule is one Inch per gallon, so in 10 gallons there should be ideally 10 inches of fishes in total.
You should consider as well the presence of plants and gravel and any other sort of things, which decrease the water volume of 5-10% (so 10 liters are actually 9-9.5). This rule does not consider modern filtration systems.
These fish suffer genetically from a certain grade of visual impairment, so overcrowding (especially competition for food) is not recommended.
At the same time, please consider as well that schooling fish (like they are) should be kept in numbers, which means more space will be needed, so be generous.

1Pet Parents found this answer helpful

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