The temperature of the water depends on the type of life/fish you intend to keep in the aquarium.
Salt Water Fish
You should change the water in your fish tank every 1-2 weeks to maintain a healthy environment for your fish.
IN WATER!!!! (TANK!!)
Water, for starters.
You should change the water in a fish tank regularly, typically every 1-2 weeks, to maintain a clean and healthy environment for the fish.
Not unless you had another fish in there.
It is recommended to change about 25-50 of the water in a fish tank every 1-2 weeks to maintain good water quality for the fish.
The white scale on the inside of the fish tank is from a buildup of minerals that were in the water.
The charcoal filter in a fish tank should be changed every 2-4 weeks to maintain water quality and keep the tank clean for the fish.
Betta fish will not be harmed if they are in a filtered tank. If the new tank is about the same size as the old tank you should use the old water or most of it in the new tank. If the new tank is larger so you have to add lots of new water then you should fill the new tank with the new water and let it sit (preferably with the filter running) for two or three days before adding the fish. Also when you move the fish make sure the new tank is at the same temperature as the old tank.
Yes it is important to have a thermometer in your fish tank. The temperature of the water should be between 75-80 degrees.
Your water is orange?! I should get the water tested right away and you should only be taking 25% of the water out a week or you will completely mess up your tank.