Fish in dreams supposedly means wealth. I'm not sure if that's true or not, but I think it means that the most important substance necessary for those fish to live is taken away. And you got worried because you don't want that most needed thing to go away like that. You needed the water to stay happy knowing the fish would live.
So out of desperation, you got the quickest source of that substance and put them in there hoping to preserve them, but it didn't.
Can you apply any of this with your actions, emotions or thoughts?