Filter stopped or flow collapsed
This is an emergency: circulation stopped — treat it like one
Do this firstUnplug, prime, and restart the filter; listen for hum — if silent, crack the impeller housing per manual.
Why this happens
Without turnover, oxygen vanishes and ammonia begins climbing from the biofilter stalling. Minutes matter in warm water.
How sure are we? Very high — restore flow first, diagnose cause second.
What to do right now
- Unplug, prime, and restart the filter; listen for hum — if silent, crack the impeller housing per manual.
- Splash surface manually while offline — jug pour to break film.
- If canister leaked: temporary sponge filter with air pump from another tank's seasoned sponge if available.
- Test ammonia within hours of prolonged outage — schedule extra partial changes if needed.
- After fix, keep observation hourly tonight — not tomorrow morning only.
What not to do
- Don’t leave it “until the weekend.”
Stop it happening again
Service the filter on a schedule, keep a spare sponge filter and air pump on hand, and never leave a stopped filter 'until the weekend'.
If that doesn’t fix it
Invest in backup battery air if outages are common.
Catch this earlier next time — log your water parameters in App-aquatic. Free forever.
This isn't veterinary advice - it's a directional read to help you decide your next step, based on the most common causes. We can't see your fish, so pair it with a liquid test kit and clear photos, and see an aquatic vet or a trusted local fish shop for a valuable or seriously ill fish.