That just might be it.
There is definitely significance to the # 8 in Asian or Chinese (not sure which) culture. A lot of the good fish stores down my way are owned by Asians, and you see a lot of #8 around. I asked a guy about it on an arowana for sale for $1888, and he said something about it being good fortune to the fish. He also told me he would not barter because it is disrespectful to the fish to barter over it's life, only fish store ever I have seen not budge on price.