Yes you should install anaconda - why wouldn’t you? Either way install numpy before bcolz in a separate pip/conda install. I recall one of the bcolz dependencies is specified as xxx>=3.2. Hence if xxx is not installed it installs latest version which is not compatible with numpy.
I would highly recommend checking out pipenv as a modern alternative to conda, plus I believe pipenv is now actually maintained by PyPA. Besides automatically creating and switching virtual environments for you, pipenv also provides a more mature requirements management and “locking” system similar to npm — including python version requirements — and is probably a little more portable (I never had success using conda’s environment.yml across 2 different machines), though you may need to rm Pipfile.lock; pipenv install on a different system, due to the system-specific nature of python dependencies.
Of course, I had to do some steps first. The detail is below.
1] first I had to create a new virtual environment with
conda create --force -n fastai python=3.7.3
fastai is the name of your virtual environment python=3.7.3 can be changed to your preferred version but I recommend to use the latest version > 3.7
2] then install fastai