Airbus first officer reported strong odor of fish during preflight resulting in an aircraft swap.

Attributes
ACN	1634728
Time
Date	201904
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Airbus 318/319/320/321 Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

Airplane was towed to gate. After the safety inspection was completed we were allowed to board. The entire cabin and flight deck smelled like fish. The APU; air conditioning packs and APU bleed were on. The cargo bins smelled normally. The smell was so intense that the entire flight crew had to deplane after a short stay on board. After reporting the issue to the gate agent; dispatch and the ZZZ chief pilot; we were given a tail swap to operate flight from ZZZ to ZZZ1. [Aircraft] was then assigned to a different flight crew. I recommend that the airplane be sufficiently cleaned before being assigned to another crew after we reported the problem.

Original NASA ASRS Text

Title: Airbus First Officer reported strong odor of fish during preflight resulting in an aircraft swap.

Narrative: Airplane was towed to gate. After the safety inspection was completed we were allowed to board. The entire cabin and flight deck smelled like fish. The APU; air conditioning packs and APU bleed were on. The cargo bins smelled normally. The smell was so intense that the entire flight crew had to deplane after a short stay on board. After reporting the issue to the Gate Agent; Dispatch and the ZZZ Chief Pilot; we were given a tail swap to operate flight from ZZZ to ZZZ1. [Aircraft] was then assigned to a different flight crew. I recommend that the airplane be sufficiently cleaned before being assigned to another crew after we reported the problem.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.