Fish is often done with the feet in lotus, though if lotus is not available, you can keep the legs straight, which is the version I’ll describe here. While sometimes practiced on its own, it is most often taken as a counter-pose, allowing the neck to experience a contrary movement to the somewhat extreme flexion of shoulderstand and plow. Be patient and listen to the body as moving from one extreme to another without sufficient care can increase rather than decrease pressure in the neck.
To begin, lay down on your back and extend the arms by your side with the forearms touching the side of the torso. Some people place the hands underneath the glutes here. Figure out what works best for you. On an inhale, press the forearms into the floor and lift the torso up away from the mat. Broaden across the front of the chest and shoulders and drop the head back to place the crown of the head on the mat (If it’s available. If you can’t comfortably arch that much, simply place the back of the head on the floor). For this variation, you want the majority of your weight to be on the forearms. If you feel strain or discomfort on the front of your neck, back out a little bit by rolling a little more to the back of the head.
Generally, you would hold for as long as you need to feel like you have countered shoulderstand, though if you are taking the pose on its own, feel free to hold as long as feels comfortable. To come out, press into the forearms again, extend the spine and let the spine come gently back to the mat.
If you have any questions, please leave a comment below. I’d love to hear from you or see you at one of my classes!