Keeping the water clean in your goldfish aquarium will not only make your fish more likely to spawn but will also greatly improve the health of your fish and any potential fry, so yes you should keep your goldfish's water clean for them to spawn.
Zero, goldfish need very clean cool water and are very dirty fish.
Have a good filter and do 50% water changes every other week.
Use a filter and try not to give it too much food. Sometimes it won't eat all the food and the water will cloud up faster from the dissolved food. also it depends on the tank if its big one you could buy one of those suker fish to clean it for you they wont kill your fish and you never have to feed them
You feed it the same amount as any other goldfish which is whatever it can eat in five minutes once a day. Be sure to remove any uneaten food you can to keep the water clean.
It just needs to be clean I don't know if a goldfish can even live in salt water. I always put the ones I've had in tap water that set out for a day or two I don't know wye it needed to sit out for a couple of days before putting the fish in it but that's how my mom always did it so I figured it was probably for a good reason. I actually had one goldfish that lived for like 4 or 5 years that's a long time for a goldfish. Goldfish need to be kept in fresh water, they are not made to live in salt water. preferably, keep them in spring or kangen water. By the way, you mom left the water out for a day or two to get it to be room temperature. Goldfish need to live in water the temperature of 70-75 degrees Fahrenheit.
Most people would keep goldfish in a bowl or tank, filled with water. You can always add scenery such as pebbles plants and castles :D
Make sure she has plenty of food and clean water. Keep her cool and just wait until the babies are born.
You should keep the water at room temperature.
If it is a small goldfish, it will physically fit in something that small. But, it will not live very long in it. If you wish to keep goldfish alive, you need at least ten gallons of water for each goldfish along with a good filter and a heater to keep the water temperature stable. With proper care goldfish can easily live 15+ years.
A goldfish can live in an opaque glass tank as long as you keep up with necessary water changes. Like a small outside garden pond goldfish are only viewed from the top.
Give it a good home, feed it, and change its water
None. Goldfish are coldwater fish. (Keep below 70F). All the sucking catfish that I know of are warm water (tropical) species. (Keep above 70F).