During hot weather, guppies often look “hungrier” because they’re more active — but heat also reduces oxygen availability and increases the speed at which waste breaks down. That means heavy feeding in a heat wave can push a tank into stress quickly. The goal in summer isn’t maximum growth; it’s stable oxygen and stable water.
Why heat changes feeding needs
- Warm water holds less oxygen: fish breathe faster and stress rises.
- Food breaks down faster: uneaten food rots quicker, raising organic load.
- Bacteria consume oxygen: more waste means more oxygen demand.
What to change during a heat wave
- Reduce portion size: feed smaller meals that disappear quickly.
- Prefer cleaner foods: high-quality pellets/flake in modest portions over messy foods.
- Skip “extra treats”: the tank’s stability matters more than variety for a few days.
- Feed earlier or later: avoid the hottest part of the day if tanks are warming.
Signs you’re feeding too much in heat
- fish hang near the surface more than usual
- water looks hazy or smells “off”
- leftover food reaches the substrate
The best pairing: aeration + lighter feeding
The safest summer combo is increased aeration and slightly reduced feeding. A stable tank with modest feeding produces better colour and health than a heavily fed tank that swings into low oxygen stress.
Heat waves don’t have to be dangerous. Make feeding “boring” for a few days, keep oxygen high, and your guppies will handle summer far more comfortably.
