Misc: A pregnant goldfish is called a?

Questions

which car maker produced the car known as the javelin?

which elementary particle orbits the nucleus of an atom and has a mass 1836 times smaller than that of a proton?

what was tv's top-rated series from 1957 to 1961?

in the movie 'spaceballs', what character did joan rivers play?

on the tv show 'seinfeld', what is kramer's first name?