Cut the tofu into any shape that you wish your "fish" to be, such as sticks or patties.
Add 3/4 cups water, 1/2 tsp salt and 1/2 tsp kelp powder to a shallow dish to make a marinade.
Place tofu in the marinade and turn it to get the kelp flakes stuck to all sides.
Let it sit for at least 15 minutes, or cover and refrigerate for up to 3 days. (The longer you let it sit, the fishier the flavor).
When you are ready to fry
Add 3 cups of oil to a pan deeper than the tofu is thick. (This will allow it to float). (Or use a deep fryer).
Heat oil to 375°F (190°C) and have it prepared as the 'fish' will be added once it is battered.
Make the batter
Combine 3/4 cups flour, 2 tbsp cornstarch, 1/4 tsp baking soda, 1/4 tsp baking powder, and salt in a bowl (optional: 1/4 tsp onion powder and 1/4 tsp paprika).
Add 3/4 cups water and stir until it forms a pancake-like batter.
Coat the marinated tofu in the batter.
Place in the hot oil immediately, pulling your hand back quickly as to not get splashed.
Fry for about 3-4 minutes until the bubbles have died down a little and it's golden brown. Flip the "fish" if necessary.
Serve hot with tartar sauce!
Notes
To Bake the Vegan Fish
Pre-heat oven to 425°F (220°C).
Batter the "fish" and place on a cookie sheet that has been lined with parchment paper.
Bake for 20 minutes.
For Gluten-Free "Fish"
Most all-purpose gluten-free flour mixes work well.
I find that they need slightly less water than traditional flour, so add about 1/2 of water and then slowly add more until you get a pancake-like batter.
If you want a gluten-free vegan sandwich bun, I find that the Schar brand works well.