Somewhere away from disturbances like next to the door and somewhere away from direct sunlight. (Keep in mind that aquariums need electricity)
If you are going from the pet-store's tank to yours you should place the whole bag into your tank for at least 30 minutes then release the fish. If you are going from your tank to another tank you should wait until the tanks are the same temperature then go from one tank to another.
if there is a black out and you do have a fish tank you should be fine an less you have a chinease fish or any fish that is in the red mark for fish
Best location for fish tank is the North wall NW. NW is moving zone, and North is water zone therefore fish tank should place in North wall towards the west zone. Check my Vastu video tips. ( AstroVastu ForYou )
You should change the water in your fish tank every 1-2 weeks to maintain a healthy environment for your fish.
You should not put your Betta fish in the same tank in the first place, most likely the male will kill your other fish. by res do you mean red eared slider?
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.
You should have it running for about 2-3 days before putting fish in your tank.
Water, for starters.
Both fish, and fish tanks, come in different sizes. So the number of fish that ideally should be in a tank, depends. Somewhere between one and a hundred would be normal.
Not unless you had another fish in there.
Salt Water Fish
IN WATER!!!! (TANK!!)