If you use an ordinary 15W submersible pump, put it in the tank, if the leakage, the fish will hang it?
Submersible pump even if it really leakage, it will not cause the fish electric shock. The so-called leakage is the submersible pump wire or shell broken, live parts and water contact, the most extreme test is a fire line directly into the fish tank
What will happen then? The aquarium glass is an insulator. The water in the fish tank has the same potential as the live wire, and the fish is like a bird standing on the fire line. No electricity flows through their bodies, so they won't get electrocuted. But if you put your hands into the water, you will get an electric shock, because the line voltage through the water, then your body and the earth to form a loop, current flowing through your body you will get (of course, if you stand on the insulator does not get an electric shock)
If the fish tank is made of metal, the fish tank is grounded or connected to the zero line, and then the fire line is put into the water, then your fish will be electrocuted immediately. Go back to the submersible pump, submersible pump line and the zero line very close, even if the firing line and the zero line at the same time the leakage occurs, fish could not swim between the firing line and the zero line, so the tank submersible pump leakage will cause the following hazards: 1, electric shock. 2, submersible pump short circuit. 3, the submersible pump serious fever, resulting in water temperature tank.