Fish are picky about temperature, just like you with your morning coffee. Most tropical fish love water between 76–82°F (24–28°C). Use a reliable aquarium heater and a thermometer. No guesswork, please!
How Do You Properly Prepare Water for a New Aquarium? - Aqua Revolt
Fill your tank with the conditioned water, then slowly bring it to temperature before adding any fish. A sudden change is like jumping into an ice bath—shocking and not fun. Slow and steady wins the fish race.
