Fish Gathering at Surface After Power Outage

[Leebtattoos]

When a canister filter sits for even 4-5 hours without running, anaerobic bacteria can become a serious problem.
When the filter is started back up that bacteria will deplete the o2 completely. Causing the fish to sit on the surface and die of not corrected.

Water changes, added surface agitation and added air stones would be suggested imo.

It’s happened to me. Sucks.

 

[Leebtattoos]

When a canister filter sits for even 4-5 hours without running, anaerobic bacteria can become a serious problem.
When the filter is started back up that bacteria will deplete the o2 completely. Causing the fish to sit on the surface and die of not corrected.

Water changes, added surface agitation and added air stones would be suggested imo.

It’s happened to me. Sucks.

 

[Nick Park]

Thanks everyone for the input and advice. I did another 50% water change last night, and also installed a powerhead with venturi to blow more oxygen through the water. Today it's a happy tank and looking like no losses.