The White Family Goldfish are two goldfish bought by Papa in the Growing Up With Hello Kitty segment Going to the Bathroom.
Description[]
It had been raining for days, and the girls were stir-crazy, so Papa brought home a goldfish, which the whole family, especially Hello Kitty, liked very much and found cute. For the rest of the day, Kitty did not leave the goldfish's side unless Mimmy or Mama were near, as she thought it would be lonely. The next day, Papa bought another goldfish to be the first's friend.

Hello kitty fish as seen in Hello kitty and friends supercute adventures
The first goldfish, implied to be a female, is a darker orange, and the second is a lighter orange. They look a bit like Siamese Fighters, but are not.

Hello kitty fish as seen in The adventures of hello kitty and friends