Goldfish Gasping at Surface After Filter Change: Oxygen Issue

Fantails at Surface After Filter Motor Swap? Check Oxygen

99-gal tank, 5 fantails, new filter motor, now gasping at top. Water tests "perfect" but oxygen wasn't tested.

Likely Cause

New motor = less flow/surface agitation = lower O2. Goldfish are sensitive; fantails especially.

Fixes

1. Add air stone + pump (immediate O2 boost).
2. Test O2 (kit ~$10).
3. 20% water change (fresh O2, removes organics).
4. Fresh activated carbon in filter.
5. Aquarium salt 1 tbsp/5 gal (stress reduction).

Stocking

Max 10 fantails in 99 gal. You have 5 — fine if filtration/O2 adequate.

Peas help constipation, but gasping = oxygen first.