My turtle died, because a lot of days without changing the w

  About 10 days without changing the water, and two days before I put them together to move to the balcony with the sun on the cylinder are also good, said today that changing the water, the results of its eyes are closed, the pinch is soft. The body where the meat long raised a lot of small white things, do not know is dead or dirty water, dead, or starved to death? I do not know how much to feed, you can only feed a little every few days.
Tortoiseshell length 2 cm a little bit more. Very small. Is to buy bags of feed grain turtle, I do not know how much Feeding Amount?

What kind of tortoise?

On the map that I do not know, bought when I thought it was not a turtle,

If it is in nature, or the flow of water, the turtle's adaptability, survival ability. You then point and where the water is dirty, then how can I bear a small turtle.