SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/fish-goldfish-not-with-tropical

Why can goldfish be a poor match for many tropical fish?

Their temperature needs can differ.

Start playing free

  1. Goldfish need saltwater
  2. Their temperature needs can differ ✔
  3. Goldfish only eat live food

Why: SRAC gives goldfish an optimal range of about 65°F to 75°F, while Merck says tropical fish need water near 77°F. Research every species before mixing fish because their safe ranges may not match.

Huh, didn't know that: Goldfish can tolerate a wide temperature range when changes happen gradually.

The dad joke
What did the ocean say to the fish? Nothing, it just waved.
Like this card?
Play the game

References

Answer: Their temperature needs can differ. SRAC gives goldfish an optimal range of about 65°F to 75°F, while Merck says tropical fish need water near 77°F. Research every species before mixing fish because their safe ranges may not match.

  1. Southern Regional Aquaculture Center Publication 7201: Species Profile, Koi and Goldfish shellfish.ifas.ufl.edu/wp-content/uploads/Handout-2_SRAC_koi-and-goldfish.pdf
    Their optimum temperature range is about 65 to 75°F (18 to 24°C)
    Checked 2026-10-11.
  2. Merck Veterinary Manual (pet owners): Special Considerations for Fish www.merckvetmanual.com/all-other-pets/fish/special-considerations-for-fish
    Tropical fish need water kept near 77°F (25°C)
    Checked 2026-10-11.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Fish & AquariumsDoes a goldfish tank usually need a heater?Fish & AquariumsHow does cooler water change how much a goldfish eats?Fish & AquariumsHow long can a well-cared-for goldfish live?

That's stuff everyone should know.