Place flour, onion salt and curry powder on a plate and mix them well.
Add the breadcrumbs to a plate. I like to add these a little at a time as I am breading the fish nuggets to prevent them from "gunking" up.
Dip the fish into the flour mix, then into the egg and finally into the breadcrumbs.
Heat the 1-1.5cm (½") oil in a 30cm or 12" frying pan to around 170°C or 340°F and batch fry the fish until it is golden brown, this will take 1-2 minutes on each side. Do not overstuff the pan, 2-3 batches are required to cook the fish, you can keep it warm in a moderate oven whilst you finish.