Well first there are many problems with the species selection in general. Betta/fighting fish are freshwater fish who are supposed to live in warm water. The starfish is a saltwater inhabitant and wouldn't be able to survive in a freshwater tank anyway. Snails should be fine in the tank, but betta fish would wreck goldfish. Those belligerent ********. Additionally goldfish are cold freshwater, so they probably wouldn't be able to occupy the same living space regardless. Betta fish are aggressive little critters who should be kept alone.
tl;dr, it would die anyway, no, yes