colombian shark

Question
We just added a columbian shark to our fish tank two days ago and he seems to really be stressed.  He has been swimming at the top only (next to the airrator (sp?))  He is swimming kind of crazy, however he does eat.  I had the water tested before we purchased him and the nitrites were a little off (inbetween <.3 and .3).  Could this affect this poor little guy?  I was going to remove and replace about 25% of the water but I am affraid I'll mess him up even more.  What do you suggest? I cannot stand to see them die.  Thank you for your time and advice.   Angie

Answer
Hi Angie,
Thank you for your letter. The first rule of sick fish is to quit dumping extra food into the water. Your shark is probably reacting to water that is polluted with uneaten food.
Here is my page for holistic aquarium care. Please buy a bottle of Cycle and follow the emergency instructions at the bottom of the page. Please print out the instructions for future reference:
http://steamboats.com/aquarium.html
Write back if you have further questions.
Nori