What is Fish ?

Fish is a fully-equipped command line shell (like bash or zsh) that is smart and user-friendly. fish supports powerful features like syntax highlighting, auto-suggestions, and tab completions that just work, with nothing to learn or configure. 1

STEP1

Install Fish from the Opensuse Debian Repo;
Check your OS version - the following commands are for Debian 8.x Jessie;

echo 'deb http://download.opensuse.org/repositories/shells:/fish:/release:/2/Debian_8.0/ /' >> /etc/apt/sources.list.d/fish.list 
apt-get update
apt-get install fish

STEP2

Change the current shell session from Bash to Fish;

fish

Set the default shell for the current user to Fish;

chsh -s /usr/bin/fish

OH-MY-FISH:

Run the following commands to Install oh-my-fish:

curl -L https://github.com/oh-my-fish/oh-my-fish/raw/master/bin/install > install

fish install

omf update

Install theme lolfish

omf install lolfish

For more information on oh-my-fish themes and other packages check out their github page

Fish shell with oh-my-fish