aquatic turtle sicknes

Question
my best friend sam has 4 aquatic turtles there are 2 red eared sliders and 2 map turtles. there is on slider and one map that are older and bigger. and the other map and slider are younger and smaller. she has never had any problems with any of them at all and she has had them for awhile now. the other day she saw that the smaller map was at the bottom of the tank dead.. its head was all ripped up and there were alot of pieces of shell at the bottom of the tank. figuring that the other turtles probably ate it? still dont no if they mayb killed it? she cleaned all the water and tank and everything and she noticed that the turtles are pale and there are some green spots on there shell it looks like mold kind of. is it maybe the start of shell rot? or is it cuz they ate part of the other turtle?
thank you

Answer
There are a lot of possibilities, and without a lot more data, I am only guessing.

One thing to point out is that she is housing two species that do not always get along together- Red-ears are big, aggressive turtles that are semi-territorial. Unless her habitat is HUGE (and I mean in the area of about 200 gallons or more), they are crowded and stressed- and getting more so every day.

One way turtles sometimes show stress, overcrowding, or aggression is to attack a smaller animal. They did not kill it to eat it, although they will certainly take advantage of the free food when it is there.

The green spots are probably mold, algae, or something similar.

What I would recommend is to do a complete evaluation of the cage, cares, and diet and fix what needs to be fixed to keep the other turtles happy.

A good place to start is http://www.redearslider.com

When she is ready for more advanced information, try http://www.austinsturtlepage.com

Good luck!