mixing fishes

Question
Can I put a beta fish and a gold fish in a tank together


Answer
Hi,
No. Bettas are tropical fish, so need warmer temperatures and different water qualities to goldfish, which are coldwater fish. They would not appreciate being in a tank together, and the Betta would probably kill the goldfish, as he would think it was another male Betta.
Also, goldfish need a lot of space, at least 45 litres per fish, and they also need strong filtration.
So, no, I do not recommend it.
Best Wishes,
Kathryn