12 in
a tank with a filter make sre the tank is big because the fish can get up to 4 feet big
It depends how big your Koi is and how big the Catfish is. If the catfish can fit in the Koi's mouth than it will get eaten.
nine inches
no if you are trying to catch catfish use clams. worms might work and big catfish will bite anchovies
The catfish that live in the pacific northwest get fairly big. The average size of these catfish ranges between a total of 40 and 50 pounds. These are also known as Channel catfish.
(holding my hands out pretty wide) about this big.
It depend on what species you plan to keep and how long you plan to keep it.
La pasion
Up to 400lb
People, and other catfish if the one is big enough to eat the other... that's about all I could think of.
You will probably get infected by the bite, and have a bad cut.