fantail and its tank size

Question
I have a huge fantail that I am currently keeping in a tank with two other smaller fantails and now a algea eater.  They are all in a twenty-nine gallon tank and I was wondering if it would be best if I had it placed in a koi pond.  I am afraid that it is outgrowing it's surroundings, even though I have been told many times that it is not.  The tank is odd shaped, taller than it is wide.  The fish seems to be hardly able to move and the smaller ones are also starting to grow in size.  Thank you for whatever advice you give me.  

Answer
Hello Brittany-

It's probably best to move the fish, especially if you notice that they are having trouble moving. Relocating them will allow them to grow to their full potential, and leave them much healthier since they will not have to compete for air, food, oxygen, space, etc.

It's really up to you - If they were under my care, I would move them to either a larger tank or, as you mentioned, a pond.

Good luck!
-Amber Worman