Feeder fish should be cared for in the same way you would care
for any other freshwater fish if you choose to keep and raise
them
What water do goldfish go in?
It depends on the fish. If its a tropical fish that is
accustomed to salt water, you need salt water and you need to keep
the water at a warmer than norm temperature. If its just a regular
goldfish, freshwater at room temp should do just fine.
Can you keep gold and black swordtails in the same aquarium?
Yes. They are both freshwater tropical community fish and should
get along well.