Heat oil to 350 degrees. In a large bowl, mix mustard and pickle juice. In a another wide bowl, add fish fry. Dredge fish strips through mustard/pickle juice to moisten, then roll in fish fry to coat. Fry in oil until golden brown, about 3 minutes per batch. Drain on paper towels.
Warm the tortillas, warm the pepper jelly for a few seconds in the microwave. Assemble each taco with a warm tortilla, fried fish strips, a drizzle of warmed red pepper jelly, and cold cole slaw.