1. The salted fish is not cleaned, and there may be mucus-like substances on the body, which can easily produce bubbles in the frying process.

2. Frying the fish with too much heat will make the oil temperature too high, which will also easily lead to bubbles.

Overall, the preparation of ingredients and the control of fire are the reasons affecting the generation of foam in frying fish. You can solve the problem by corresponding methods:

1. When you deal with salted fish, make sure to wash it carefully to remove the mucus material on the surface, which can reduce the foam when frying.

2. During the frying process, control the fire well to avoid the oil temperature being too high. You can try to turn down the heat and then lower it appropriately if the oil temperature is too high.

The above are some of the methods I have provided for you, I hope they are helpful to you. I believe that you can also make delicious fried salted fish if you master the correct preparation methods and techniques!