I follow conda_PR_545, conda issues 4221 and still not working on Ubuntu.
After downloading conda.fish from here, and mv it to anaconda3/bin/.
Add \"source /
Adding conda's bin directory to PATH isn't recommended as of conda 4.4.0 https://github.com/conda/conda/blob/master/CHANGELOG.md#440-2017-12-20
All you need to do is adding source /etc/fish/conf.d/conda.fish to config.fish.
source /etc/fish/conf.d/conda.fish