I have eaten expired cookies and expired chocolate and drank expired milk and I am still typing here.. hahah
well, it is fine so long the food are not mouldy or stinked..
and you must also understand the term Expired or Best Before means..
Best before - a term used to claim that their product taste better before this date.. if you consume it after that date, quality is not gauranteed.. but it does not mean it is spoilt yet.. provided it is properly stored and not too long after the date specified..
Expired - means whatever active components or chemical presence is no longer active.. so this item is no longer useful after the specified date.. for food, it may means it is not spoilt but the ingredient is no longer active.. thus all vitamin and nutrients are not available or not active anymore.. but do take note for some food may be expired and it may turn toxic which does not apply to your god fish food case.. so dun worry... maybe the food is not providing anymore proper nutrients to your fish but no harm done...
dun forget, I am still alive and still typing after eating so much expired food.. : P
p/s: for those who wonder why I ate so much expired food.. becuz I love buying even though I dun eat so much.. worse of all, I dun clean out my fridge.. opps..