Water and hot oil = fire. Make sure your fish is dry (pat it with a tea towel before frying it) and not frozen. If there is a fire, get a wet towel and place it on the fire. DO NOT ADD WATER!
It'll spit quite violently when you put the fish in, but that's normal. Just don't leave it the pan when it's cooking. Then, when you've finished cooking just take the pan off the heat and put it to one side. Don't pour water into it until the oil has cooled down. Alternatively, you can reuse the oil (pour it into its own container WHEN IT'S COOLED, and label it 'frying oil' or something).
I worked in a chippy for 5 years (so had lots of open hot oil), we only had one fire which was caused by someone being a total idiot. They are quite rare if you have a bit of common sense.
Best of luck.