can i put a t5ho light in my 20 gallon stock top or will it blow the fuse in my house
A T5HO lamp that would fit in that housing, would be 27 watts or less. If that blows a fuze or pops a circuit breaker, you've got other issues to worry about.
The problems will be ventilation, mounting, and a reflector.
T5HO lamps/bulbs/tubes run hot.