Hi ,
I am new to this site and I been searching everywhere to get the answer to my question. Your site is very useful also. My question is that -- I have a 20 gallon tank with 3 small comet fish , 2 inch angelfish and a black tetra also about 2 in. I really want a KOI but do not have a pond. I have no where to put a pond so the pond is out..

I was wondering if my tank is alright to get a baby KOI ? My tank isn't that crowded with Decor either. I have a fake plant and a fake log in it. Is my comet fish going to be big like a KOI ( meaning do they grow the same way as fast ) I really want one but I don't want it to die.
Thank You ,

PLEASE E-MAIL ME BACK ASAP

Stephanie , New York

Dear Stephanie,

Your Comet will be just fine in the 20-gallon tank, although the Angel may bully it. Angels are ciclids, and usually don't tolerate other breeds of fish. The comet will grow slowly under these conditions; its growth will be limited by pheromones secreted by the fish in this small tank.

I am sorry, but even a baby koi will overload your tank. Most aquariums do not have filters that can keep up with koi waste production. The best estimate for water needed for *small* koi is 25 gallons per inch of koi, and that is heavily biofiltered water. As a koi grows (and they grow very fast indeed), this increases as the koi exceeds 6 inches to 50 gallons per inch of koi. Koi do not do well indoors.

Bob Passovoy
President
MPKS