What can cause the water in my fish tank to put off an electric shock, well I am assuming its an electric shock, I had a toad fish in it, but it died. And now all that is in there is groupers, a catfish and a bunch of little school fish. its a 75 gallon tank, and proves to be difficult to clean. If anyone has any suggestions on that too. But it comes and goes and when u touch the water it shocks you occasionally. I need a new light for it too because the light is old and the left side doesn't always turn on. Anyone know where I can get a cheap 75 gallon light? (shock might be from light, however I don't see any water getting to the light, I have moved it away from the filters)