well for one, they do feed them, just not enough, most of their fish die in the tanks, but they arent so good at taking them out...the water DOES go stagnate. no filter can change that. wal-marts is never changed...
as for cheap fish tanks, just a glass globe. thats about the cheapest, and then...
Yes its possible. thats why they have Anti freeze engine coolant. the heat will get so intense it will warp parts of your engine, then you can say "goodbye car". you must have coolant, just like you must have oil.
i have seen it happen, its happened to a cousin of mine.
well its obvious she likes him, just make sure she isnt being threatened by the bad guy. it could be that. tell your good friend to man up and steal her away. be the knight in shiny armor!