Most guppy health issues start as stress, and the most common stressor is water quality (ammonia, nitrite, temperature swings, or low oxygen). The earlier you respond, the less likely you’ll need medication. Think of this as a triage guide: stabilise the environment first, then decide if treatment is needed.
The 60-second observation
Before you do anything, watch the tank for one minute:
- Breathing: normal = steady gill movement. Rapid breathing = oxygen/temperature/water issue.
- Posture: fish should stay level. Tilting or sinking can signal serious stress.
- Fins: open fins = comfortable. Clamped fins = stress signal.
- Behaviour: cruising and pecking = normal. Hiding, darting, or sitting still = something is off.
Test first (not later)
- Ammonia (should be 0)
- Nitrite (should be 0)
- Nitrate (indicator of long-term load)
- pH (mainly for stability and context)
If ammonia or nitrite show anything above 0, treat that as urgent: do a 30–50% water change, increase aeration, and reduce feeding for 24 hours.
Common signs and what they usually mean
- Clamped fins: stress from water, temperature swing, or bullying. Fix environment first.
- Flashing/scratching: check nitrite/ammonia. If water is clean, consider irritation or parasites.
- Gasping at the surface: low oxygen or high temperature; increase surface agitation immediately.
- Stringy white poop: often diet/stress. Pause rich foods 24 hours and offer spirulina/peas.
- White spots (grain of salt): likely ich; stabilise temp and follow a targeted treatment plan.
When to medicate
Medicate when you have a clear target and the tank is stable enough for fish to handle treatment. Medication in unstable water often fails because the stressor remains. If you’re unsure, isolate the affected fish (if possible), improve oxygen, keep water pristine, and observe carefully.
The best health “secret” is boring consistency: stable temperature, routine water changes, and not overfeeding. Healthy guppies are resilient — stressed guppies are fragile.
