As of fish 2.6.0 conda 4.3.27: the following steps may change as issue is addressed

update config

Take note of your conda‘s location

conda info --root
/Users/mstreeter/anaconda    # this is my <PATH_TO_ROOT>

Add line to ~/.config/fish/config.fish

 source <PATH_TO_ROOT>/etc/fish/conf.d/conda.fish

update convention

Typically you’d run the following from bash

source activate <environment>
source deactivate <environment>

Now you must run the following from fish

conda activate <environment>
conda deactivate <environment>

issues

so after doing this I’m not able to set fish as my default shell and have it still work properly with conda. Currently, I must first enter my default shell, and enter fish and the shell works as expected. I’ll update this after I find out how to get it working completely without the need to explicitly choose fish each time I log into my terminal