Fish Pose

Physical Benefits:

• Corrects the tendency to hunch the shoulders.
• Develops lung capacity.
• Relieves tension and congestion in the lungs.

Process:

• Lie flat on your back with your feet together. Keep your legs straight and together throughout the posture.
• Tuck your arms under your body with palms facing down. 
• Push your elbows into the ground and support your weight on your elbows.
• Lift your chest till you are half sitting up.
• Now slowly move your head down to the ground. Put as little weight as possible on your head and relax your throat.
• In this posture, chest will remain expanded.
• To come out of the posture, lift your head slightly and lower your back in the ground.
• Relax in shavasana (corpse pose). Gently roll your head from side to side twice and bring it back to centre.

In case of tension in neck after practice:

• Interlock your fingers behind your head and hold your forearms close to your ears.
• Inhale and life your head.
• Push your chin into your chest.
• Lower your head slowly back on the mat.

Counterpose:

Fish Pose is the counterpose of:

• Shoulderstand
• Plow

Tridoshas link:

• Vata - It helps in expanding the narrow rib cage of Vata allowing for greater vital energy.
• Pitta - It helps in relaxing the ambitious Pitta nature.
• Kapha - It helps Kapha people by acting as a decongestant.

References:

Primary Reference: Practical Ayurveda - Fing out who you are and what you need to bring balance to your life - Sivananda Yoga Vedanta Centre - Pg 142-143