Are you positive you have a shubunkin, and not a koi? Koi eat tadpoles. In my
yard I have a koi pond, and a goldfish pond....lots of tadpoles in goldfish
pond, and none in koi pond, even though many large frogs live in it...This
would also explain why it is larger than the others.....the ONLY way for a
novice to tell the difference is the koi has barbels ( whiskers) and while
under 6 or 8 inches they are sometimes very hard to see.......Jerri

http://www.fringeweb.com/Ponds/JerrisPond