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.
2 or 3
a fish tank size would depend on the size or how many fish you want to put in or if its tropical the tank would have to be measured and remember to get the water tested you don't want to kill the fishs
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
The mass of a fish tank should be measured in kilograms.
not too many because they wont be enough space for it to roam
I have 6
Only 1. Usually a Betta is all that is kept in a 3 gallon tank
You should have it running for about 2-3 days before putting fish in your tank.
Water, for starters.
6
IN WATER!!!! (TANK!!)
Not unless you had another fish in there.