Squeeze the limes as close as you can to the moment of serving so they don't go bitter and keep them with an ice cube as you're squeezing them. Remove the ice cube before blending.
Put everything in the blender and pulse 3-6 times or until you see everything's now in small chunks.
Pass through a sieve and press down to really get all the juices.
Taste the tiger's milk and adjust the level of salt. Also if it's too sour add sugar. You'll especially need sugar if you're outside Perú and the limes aren't as sweet. You should be able to drink it and enjoy it on its own even without the fish.
Mix the leche de tigre with the fish and other ingredients and serve immediately with coriander, sweet potato and Peruvian corn.