How many 1.5 inch goldfish can a fiftyfive gallon aquarium hold?

Although the goldfish are very small and it may be tempting to put many goldfish in a tank that large, you have to resist these urges if you want your fish to be happy and healthy. Keep in mind that goldfish grow very large: 6-8 inches for the fancies, 6-12 inches for the more common ones. The rule of thumb "one inch of fish per gallon" just does not work with goldfish. A more accurate measurement of goldfish per gallon would be " for each inch of goldfish allow 3-4 gallons of water". Hope this helps- and remember though the fish are small now, they will soon grow very large and beautiful.