Air stones are one of those aquarium items people either swear by or ignore completely. The truth is simpler: guppies don’t need bubbles for fun, they need oxygen exchange. Air stones improve oxygen and circulation, but they aren’t always required if your tank already has good surface movement. Knowing when you actually need one helps you keep fish safer without adding unnecessary gear.
What an air stone really does
The bubbles themselves don’t “add oxygen” directly in a magical way. The main benefit is that rising bubbles move water and create surface agitation, which increases gas exchange. That helps oxygen enter and carbon dioxide exit. In warm weather, after shipping, or during treatment, that extra exchange can be the difference between stable fish and stressed fish.
When you should strongly consider an air stone
- Summer heat: warm water holds less oxygen.
- Heavily stocked tanks: more fish = more oxygen demand.
- After shipping or new arrivals: stressed fish breathe harder.
- During medication: many treatments reduce oxygen availability.
- At night in planted tanks: plants consume oxygen when lights are off.
When you probably don’t need one
If your filter outlet creates strong surface rippling and fish show no surface gasping, an air stone may be optional. Many guppy tanks run perfectly fine with good filtration and surface agitation alone.
Signs oxygen is low
- fish hanging near the surface
- rapid gill movement
- lethargy that improves after increasing flow
- stress after water changes or during warm days
Using air stones without stressing long fins
Air stones can create turbulence. If you keep premium long-tailed males, position the stone so bubbles rise in a corner and don’t create a strong “washing machine” effect. Gentle steady aeration is ideal.
Air stones are cheap insurance. You may not need one every day, but having the option to boost oxygen quickly is one of the simplest ways to prevent avoidable guppy losses.
