koi and freshwater fish

Question
i got a 90 gallon tank with 4 koi in it...we just started the tank with them but want to get regular fish. can i keep the koi as long as i monitor the amonia level?

Answer
Hi Dan;

If by "regular fish" you mean goldfish, they can be mixed but your tank is actually not even large enough for the koi you have now to grow up in. Your koi are going to get over 3 feet long and are incredibly strong. They are jumpers and will break the lid off of your tank before they even get near their adult size. There's much more than just ammonia you have to consider. The levels of nitrite and nitrate can be elevated in overcrowded tanks too.

If you mean other types of community fish, you really can't mix them. Other types of fish require warm water tropical temperatures of 75f or higher. Your koi require cooler water. Tropical fish and koi have different temperaments and food requirements as well.

If your tank is new you will want to know about New Tank Syndrome too. Here is a link to my page about to help you through;

http://www.xanga.com/Expert_Fish_Help

Good luck!

At Your Service;
Chris Robbins