Aquarium Temperature Chart
Keep your fish healthy at the right water temperature. Typical ranges for tropical community tanks, goldfish, bettas, discus, ponds and reef tanks.
Aquarium temperatures
| Fish / tank | Temperature |
|---|---|
| Tropical community fish | 75–80 °F (24–27 °C) |
| Betta | 76–82 °F (24–28 °C) |
| Goldfish (fancy) | 65–72 °F (18–22 °C) |
| Discus | 82–86 °F (28–30 °C) |
| Guppies, mollies, platies | 72–82 °F (22–28 °C) |
| Neon tetras | 72–78 °F (22–26 °C) |
| Koi pond | 59–77 °F (15–25 °C) |
| Reef / saltwater | 75–80 °F (24–27 °C) |
| Cold-water tanks | 60–70 °F (16–21 °C) |
Notes
Stability matters as much as the number: avoid changes of more than about 2 °F (1 °C) per day. Use an adjustable heater (about 3–5 watts per gallon) and a separate thermometer. Warmer water holds less oxygen, so increase aeration in heat waves. Always check the needs of each species before mixing fish.
Frequently asked questions
What temperature should a tropical fish tank be?
75–80 °F (24–27 °C).
What temperature do goldfish need?
About 65–72 °F (18–22 °C) — they do not need a heater in most homes.
What temperature is best for a betta?
76–82 °F (24–28 °C).
What size aquarium heater do I need?
About 3–5 watts per gallon.
How do I cool an aquarium in summer?
Turn off the lights, float sealed bags of ice, aim a fan across the surface, and increase aeration — never drop the temperature quickly.