Aquarium fish that tolerate warm water (30 °C and above)
16 species from the AquaLog care guide · Updated
In short: These freshwater fish have recommended ranges that reach 30 °C (86 °F) or more, including bettas, discus, rams, many gouramis and some corydoras. 30 °C is the top of their range, not a target, and warm water holds less oxygen, so add surface movement in hot weather.
In hot summers, including much of India, an indoor aquarium can climb past 30 °C (86 °F) without a heater. Every species below has a temperature range in the AquaLog care guide that reaches 30 °C or higher, so a warm spell is less of a shock to them than to a temperate fish.
That doesn't make 30 °C ideal. It is the upper end of the range for most of these fish. Aim for the middle of each species' range and use the list to choose fish that cope better when the room gets hot.
The species
| Species | Min. tank | Temperature | pH | Temperament | Group | Care level |
|---|---|---|---|---|---|---|
| BettaBetta splendens | 20 L (5 gal) | 24–30 °C | 6–7.5 | Aggressive | 1 | Beginner |
| Chocolate gouramiSphaerichthys osphromenoides | 75 L (20 gal) | 26–30 °C | 4–6 | Peaceful | 6+ | Advanced |
| German blue ramMikrogeophagus ramirezi | 75 L (20 gal) | 26–30 °C | 5.5–7 | Peaceful | 2+ | Advanced |
| Threadfin rainbowfishIriatherina werneri | 75 L (20 gal) | 24–30 °C | 6–7.5 | Peaceful | 8+ | Intermediate |
| Sterbai corydorasCorydoras sterbai | 90 L (24 gal) | 24–30 °C | 6–7.5 | Peaceful | 6+ | Beginner |
| Pearl gouramiTrichopodus leerii | 110 L (29 gal) | 24–30 °C | 6–7.5 | Peaceful | 1 | Beginner |
| Zebra plecoHypancistrus zebra | 110 L (29 gal) | 27–30 °C | 6–7.2 | Peaceful | 3+ | Advanced |
| AngelfishPterophyllum scalare | 200 L (53 gal) | 24–30 °C | 6–7.5 | Semi-aggressive | 1 | Intermediate |
| Boesemani rainbowfishMelanotaenia boesemani | 200 L (53 gal) | 24–30 °C | 7–8.5 | Peaceful | 6+ | Beginner |
| DiscusSymphysodon aequifasciatus | 250 L (66 gal) | 28–31 °C | 5.5–7 | Peaceful | 6+ | Advanced |
| Kissing gouramiHelostoma temminckii | 300 L (79 gal) | 22–30 °C | 6–8 | Semi-aggressive | 2+ | Intermediate |
| GeophagusGeophagus sp. | 380 L (100 gal) | 26–30 °C | 5.5–7.2 | Peaceful | 5+ | Intermediate |
| OscarAstronotus ocellatus | 450 L (119 gal) | 24–30 °C | 6–8 | Aggressive | 1 | Intermediate |
| Clown loachChromobotia macracanthus | 600 L (159 gal) | 25–30 °C | 6–7.5 | Peaceful | 5+ | Advanced |
| Common plecoHypostomus plecostomus | 700 L (185 gal) | 22–30 °C | 6.5–8 | Territorial | 1 | Intermediate |
| Giant gouramiOsphronemus goramy | 1500 L (396 gal) | 24–30 °C | 6.5–8 | Semi-aggressive | 1 | Advanced |
Keeping a tank cool in a heat wave
- Increase surface movement with an air pump or by lowering the water level slightly below the filter outlet; warm water holds less oxygen.
- Keep the tank out of direct sun and away from windows.
- Turn the light off during the hottest part of the day.
- A fan blowing across the open water surface cools it by evaporation; top up with dechlorinated water as it evaporates.
- Feed a little less; digestion uses oxygen.
Large species in this list, such as the oscar, giant gourami and common pleco, need very big tanks. Check minimum tank sizes in the table.