1. Anaconda version:
my experience is only install nb_conda is enough

conda install nb_conda

2. for normal pyhton version, you need to install ipykernel in each enviornment. (Notice: following code is example for mac and linux system.)

source activate my_environment
pip install ipykernel

https://stackoverflow.com/questions/39604271/conda-environments-not-showing-up-in-jupyter-notebook/43197286