How long after will fish die if not acclimated properly?

[Miami Reef]

Do fish usually die instantly when not acclimated properly or does it take a few days?

I added new fish to my tank and a couple of them died a few days later. I know I didn’t acclimate them properly, but I have seen them looking fine for 1-2 days.

 

[Timfish]

Stress along with unseen problems can kill fish at any time. Not acclimating them and, argualbly, acclimating them both cause stress and can accerbate an unseen problem. If any fish dies within just a few days I suspect problems it had before I acquired it.

 

[LegendaryCG]

They dont die instantly but they will be visibly stressed. Acclimation depends on a lot of stuff. Shipped fish often don’t do well with slow acclimation as the ammonia in the bag is far worse on them than a salinity shift.


If I buy locally I’ll take my time acclimating them, if it’s a fish being shipped I usually match temperature and add a couple cups of tank water to thr bag over 30 mins and put them in.