Heat about 3 inches vegetable oil in a medium pot over medium-low heat until a deep-fry thermometer registers 375 degrees F. Meanwhile, toss the cabbage, cilantro, lime juice, honey and mayonnaise in a bowl. Season the slaw with salt.
Warm the tortillas in a skillet over medium-low heat or wrap in a damp cloth and microwave 25 seconds. Wrap in a towel to keep warm.
Mix the flour, chili powder, and salt and pepper to taste in a shallow bowl. Dredge the fish in the flour mixture, then fry in batches until golden and just cooked through, 2 to 3 minutes. Transfer with a slotted spoon to a paper-towel-lined plate to drain. Season with salt.
Halve, pit and slice the avocado. Fill the tortillas with the fish, avocado, slaw and salsa. Serve with lime wedges.