Who Gives A Fish Forums

My tank's been hitting 86°F lately, and my tetras seem stressed. I've got a 20-gallon with a basic heater, no chiller. Any tips to cool it down without breaking the bank?

First thing, check your heater settings. Sometimes they malfunction and overheat. If it's set right, try reducing room temp or adding a fan blowing across the water surface. Evaporation cools things down.

Yep, fans work wonders. I rigged a cheap USB desk fan over my 30-gallon, dropped temps by 4°F. Just top off water more often 'cause evaporation's gonna spike.

leafyfox wrote: ↑Sun Jun 08, 2025 5:57 pm Yep, fans work wonders. I rigged a cheap USB desk fan over my 30-gallon, dropped temps by 4°F. Just top off water more often 'cause evaporation's gonna spike.

Second this. Also, float some ice packs in a ziplock during heatwaves. Temporary fix, but it's saved my Discus before.

Long-term, consider a chiller if your room's consistently hot. Or switch to cooler-water species. Tetras can handle warmth, but not forever at 86°F.

Messed with my heater dial last summer, same issue. Turned out the thermostat was sketchy. Replaced it with an adjustable one, problem solved. Worth a check.

Thanks, all! Gonna try the fan trick first and monitor the heater. Appreciate the quick help.

Does the tank get direct sunlight? That'll crank up temps fast. My cousin's tank was near a window, and it cooked his Guppies.

jasmy wrote: ↑Sun Jun 08, 2025 7:42 pm Does the tank get direct sunlight? That'll crank up temps fast. My cousin's tank was near a window, and it cooked his Guppies.

Good point. Even ambient light from windows can add heat. Blackout curtains help if relocation's not an option.

My tank's in a basement, stays chill year-round. Maybe move it if possible? Not always doable, I know.