Heat stress makes guppies gasp and dull their colour. During Australian summers, aim to hold 26–27°C and maximise oxygen.
Fast cooling tactics
- Increase air: add an airstone; warm water holds less oxygen.
- Dim lights: shorter photoperiods reduce heat from fixtures.
- Surface agitation: point a filter outlet at the surface to gas off heat.
- Evaporation assist: run a small fan across the lid; top up with dechlorinated water as needed.
What temperatures are risky?
Above 29°C for extended periods shortens lifespan and can trigger columnaris. If your room regularly exceeds this, use a clip-on chiller fan or move the tank to the coolest room in the house.