koi acting funny

Question
i have a six inch koi living in a fish tank... i clean the water at regular intervals... but hes acting strange, not eating and hes moving like he wants to get out of the tank or something... what makes a koi stress out like this??? please excuse me for my lack of knowledge, but ive had goldfish for 8 years and im new to this koi thing... ive heard koi can live up to 100yrs so i want to treat him like one of my kids...

Answer
Hi,
Maybe the tank is too small and if you keep changing the water without passing it through a filter you will be adding what ever chemicals the water company put in the water ,maybe the PH is wrong, koi like the water neutral at 7.5 , so check the parameters of the water.,you can see my koi on my website at http://koi-z-are-us.20m.com
George.