Can i use my hermit crabs heating pad to heat my fish tank?

If it's the pad I'm thinking about, it should explicitly have instructions not to use it on glass that's in direct contact with a large body of water because it will stress the glass and cause it to break. I know this is the case for the heat mats that are used with reptiles and amphibians, and the ones for hermit crabs that I've seen are basically the same thing. See if you can find the manual online if you don't have it or call the company since you don't want to come home to a broken tank, dead fish, and a large puddle of water.

It won't electrify the water, whatever that may mean, since the heating pad is on the outside of the tank (if it's properly installed), but it won't raise the water temperature by a lot.

Noit wont work. For one thing the heat pad wont give off enough heat to adequately heat the water, for anothwer they are not desiogned to be submerged in water and yes they willelectricfy the water - dont even try it!

Just dont do it!

You never taught as a child, keep all water away from electricity??

It WILL electrify the water and make it extremely dangerous for your fish and you, it will kill the fish and will hurt you bad, if not kill you(depending on the watts/volts).

Again, just dont do it !!

yes try and avoid electrical implements around the best conductor of electricity there is: good start.

buy a heater meant for fish aquariums