what shall I do for my fish?

[NoticeableNails]

I keep cold water fish and also tropical fish.
I wouldn't introduce a new fish straight away, I would let the tank settle after the recent water change, keep an eye on your other fish for any signs of illness. If all is fine after a few days then you will be able to introduce a new fish.
HTH

 

[Jaffacake]

aww bless, I know how you feel because we have Marines and its so sad when one dies, stupid i know, but they are definately one of the family and they do have personalities believe it or not! they come and greet us when we look in the tank, especially our foxfaced rabbit fish and cleaner shrimp!

 

[Zuise.e]

I keep cold water fish and also tropical fish.
I wouldn't introduce a new fish straight away, I would let the tank settle after the recent water change, keep an eye on your other fish for any signs of illness. If all is fine after a few days then you will be able to introduce a new fish.
HTH

yes i'm going to leave it a while in case the poorly fish left anything behind.