Every fish lives in a different inviroment.If its a tropical fish and the water is to cold it will die.
When you buy fish from a retailer - their water quality might be slightly different from yours. When you get the fish home, it's always best to gradually mix in some water from your own supply with that of the water in the bag the fish is sold in. Leaving it for a few minutes will acclimatise the fish to its new surroundings.
So they get used to the height and lower atmospheric pressure.
yes they can, so long as you acclimatise them to the tank. For starters, if possible, fill your tank with water from the pond, ( I know, it probably won't be the clearest, but your fish will thank you), and once your aquarium is up and running, match the temp of the tank as near as possible to the temp in the pond, (ie, don't try and throw them in your tropical tank, they will probably go belly up!). Bag the fish, and acclimatise them to the aquarium as you would with a store bought fish. To get rid of the bugs, dose the tank and the fish with malachite?(been awhile, can't remember the spelling) blue. Hope that is at all helpful
Saltwater fish require salt water, and fresh water fish need fresh water, you can't mix them, or the fish will die. You need to look at each individual fishes needs as to what temp they need their water to be. There are some saltwater fish that can survive in fresh water, but it is not healthy for them.
Depends on the fish.
Fresh Water
Tap water. But to keep fish healthy you will need to add a chemical called Water conditioner or Water ager. This simply removes any chlorine or chloride from the water as fish cant live in chlorinated water.
It cant, fish need water to survive.
Yes. All animals need water. This includes fish.
no tropical fish need warm water
They need water Fish can not process oxygen the same way mammels do. They get their oxygen throu molecules in the water.
Fish live in the water, so generally they only need food. But they get their oxygen from the water through their gills, so they will need the water to have dissolved oxygen at a proper level.