I seen my first Koi this weekend at Lake Marburg. It was about 25 inches. Forgot camera though. Are they rare around here or do they just like to stay in deep water. I've never seen one before.

Koi is a japanesse grass carp that was introduced to certain lakes to control vegitation.    I think koi are supposed to be sterile and won't reproduce.

If you google Koi or grass carp, you will get plenty of reading material.

Matt

Koi are ornamental fish and are not introduced in any water on purpose. (unless private)

People introduce them in lakes because they got bored of them or they got to big for their pond.

Grass carp on the other hand are introduced to control vegetation.