Accidentally Fed Spoiled Mysis to my QT fish

AetherealKnight · Monday at 10:15 PM

Title says it all. Not sure what I was thinking, but for the past 2 days, I've been feeding my QT fish spoiled, thawed-out mysis that had been sitting in cup with copper-treated water since Saturday night (fed them yesterday and today).

No idea what the repercussions are gonna be or what I should do. I know people have had their fish die from food poisoning, though. Any advice on what I should do or just pray for the best :(

Justfebreezeit · Monday at 10:41 PM

Not much you can do. Id imagine they will be fine though.

AetherealKnight · 2026-10-13T11:55:10-0400

Justfebreezeit said:
Not much you can do. Id imagine they will be fine though.

Even if it’s been sitting out thawed for 2 days? Doesn’t bacteria multiply rapidly after just a few hours?

Gumbies R Us · 2026-10-13T13:01:55-0400

I'm going to tag the #fishmedic team for this one. They could give you the best idea of what you should do

Fish Fan · 2026-10-13T13:09:29-0400

I've never heard of this being a problem. I've left food out like that before. Fish are not as sensitive to this kind of thing as people are, this is like your dog eating something that would make you sick, and the dog is just fine

winxp_man · 2026-10-13T15:07:31-0400

Animals can generally handle bad food. Their gut bacteria is different vs human. The things some of these fish eat in the wild is crazy. They are built for it.

exnisstech · 2026-10-13T15:30:06-0400

My fish eat each others poop so doubt some 2 day old seafood will be an issue. Either way it's not to like you can pump their stomach or induce vomiting so it's wait and see.

Jay Hemdal · 2026-10-13T17:03:31-0400

AetherealKnight said:
Title says it all. Not sure what I was thinking, but for the past 2 days, I've been feeding my QT fish spoiled, thawed-out mysis that had been sitting in cup with copper-treated water since Saturday night (fed them yesterday and today).

No idea what the repercussions are gonna be or what I should do. I know people have had their fish die from food poisoning, though. Any advice on what I should do or just pray for the best :(

Was the food dark / oxidized?
Did it smell?

AetherealKnight · 2026-10-13T18:04:45-0400

Jay Hemdal said:
Was the food dark / oxidized?
Did it smell?

Did it smell? Not really, I still have it sitting there next to the tank (with no intentions of using it of course). It was a pretty dark mysis, so I can't really say it changed the color, it looks about the same.

Could it sitting in copper QT (2.5ppm) water inhibit bacteria from multiplying?

Jay Hemdal · 2026-10-13T19:33:57-0400

AetherealKnight said:
Did it smell? Not really, I still have it sitting there next to the tank (with no intentions of using it of course). It was a pretty dark mysis, so I can't really say it changed the color, it looks about the same.

Could it sitting in copper QT (2.5ppm) water inhibit bacteria from multiplying?

Copper is slightly bacteriostatic, but I don’t think it would work to help preserve the food.