I doubt having 9 or 10 1 inch shiners in a 10 gallon tank or 2 2inch bass in another 10 gallon tank is overcrowding. The general rule for small fish (less than 3 inches), is that you can keep about 1 inch of fish for every gallon of water comfortably. These are temporary residences until I finish the construction of my 240 gallon plywood/acrylic tank. There are only 4 shiners left now, but they look pretty healthy. Check out some pics at this other message board
http://outdoorsbest.zeroforum.com/zerothread?id=76490. On keeping pike, I don't know about keeping a specimen until maturity, you would need a tank a lot bigger than 75 gallons for that. Also, pike require temperatures around or below 72 degrees, and you probably will need an expensive (200 bucks for a cheap one) cooling device to keep the temp down.
