Sick Fish...what To Do With Aquarium Water.

[tim1]

Ok, here is the deal. I've had a 55 gallon aquarium for a couple years with a few fish in it. They grew really big, and I decided to add some more. So I went to my local pet store and bought some, and added them to my aquarium. I made a huge mistake and added a bit of water from the pet store to my aquarium, and the next day one of my sharks was dead.
I decided to give my fish away to the pet store since they were to big anyways, and I was not sure how to treat them. Now I want to introduce new fish, but I am not sure if it is safe.

My question is if the bacteria are harmful enough to get my new fish sick. Do I need to start over again(clean everything out, and then start cycling), or can I just treat the water? I'm a newbie so please be patient with me

Thanks.

 

[12azor]

How much of the water did you add from the fish shop?

Treat the water for what the fish died of and then it should be okay. In future net the fish out of the bag and add them that way.