turtle not eating and white foam like substance comming from the mouth

Question
my girlfriend and i bought 2 baby red eared turtles, we bought them online from turtlesale.com , the way it sounds is they wer born and raised in captivity weve had them for 6 months and the smaller one has stopped eating and has lost its activeness and usually just stays on the platform not caring much to be in the water, the water is at a constant 80 degrees, there is a heat lamp and a running filter the turtle has started foaming at the mouth a little and seems to breathe opening its mouth, than through the nose, ive seen this once before w my old baby turtle when i was younger, unfourtunatley it died, how can i help this turtrle its been 2 days sine it ate last, its also stayed smaller while its 2 other brothers have doubled in size, its a 15 gallon tank

im lost at how to fix the poor thing, please help.

Answer
This is not really good news. The illness is called 'infectious stomatitis' or mouth rot.

Here are some links:
http://www.austinsturtlepage.com/Care/medinjuries.htm

http://www.redearslider.com/physical_conditions.html

Stomatitis often indicates poor cares and stress, either now or at the place they were purchased from. Reviewing the sites listed above can offer good care ideas, as well as good sources for replacement turtles should you decide to go that route.