Do you have an old container you could use. (Someting like an old ice cream box, or margarine box)
Just fill with tank water.
You will have to keep changing the water.
Then once the fish looks better.
You will have to rehome it, or the krib.
Hi I am so sorry you lost your fish Had your krib just spawned ? as they are very protective when breeding and even more once they have fry, I had a pair on took back to lfs
cathy