Hello,

What you are describing sounds like a respiratory infection in turtles. If I am correct with this, he will need to see a Herp Vet for some antibiotics. There is no at home treatment for this type of problem and is very common in water turtles.

The turtle needs to be in a tank that is regulated with temps at 85*F and filtered water, along with a UVB light and basking light so his immune system does not become suppressed.

I would be happy to locate a Herp Vet for you with a State. I am also going to give you a care sheet which was created by Anna a fellow Expert. This will help with the proper set up:

SLIDER TURTLE CARE SHEET

Well-cared for sliders can live 30 years or
more.

The Tank

It's recommended that a baby slider have at least a
15 gallon tank. By the time the turtle is 3-4 years old, it will need a 60
gallon tank, so it's best to get the biggest you can in the beginning. You can
also use a large RubberMaid tote. That's not as pretty as a tank, but costs a
lot less. Set up the tank so there's a land area and a water area. Put the
basking light at one end so the whole tank doesn't get too hot. You want the
water to be about twice as deep as the turtle is long. If the turtle is two
inches long, you'll want four inches of water.

Temperatures and Basking
Area

Turtles need certain types of lighting and need to be warm. Air and
water that are not warm enough can lead to fungal and respiratory infections and
unhealthy shells. Turtles must have a basking area where they can get out of the
water, dry off, and bask in very warm light. The ambient air temperature in the
tank should be around 75 *F (24*C) , with the basking area warmer still. Over
the basking area there should be some sort of lamp that will take a 40-60 watt
incandescent bulb (or you can buy a ceramic light fixture made just for
reptiles). If you live in an area that has farm stores, you can buy a metal
light fixture made to keep baby chicks warm for just a few dollars. Don't buy
the accompanying bulb, however. You need an ordinary incandescent bulb in the
basking light. Hardware stores sell similar fixtures as work lights. The basking
area should be kept at 85-90*F (29 to 32*C). Use a digital probe thermometer to
be sure. You can adjust the temperature by raising or lowering the light
fixture.The lights that come with the covers on aquariums are not suitable for
turtles. You'll also need a submersible aquarium heater that will keep the water
78-82*F (26 to 28*C).

UVB Light

It's extremely important that you
buy an additional light that produces UVB rays. A Reptisun 10.0 is a good brand
that does. If you choose another brand be absolutely certain it provides UVB
rays. Don't take the word of pet store personnel, but read it for yourself.
Full-spectrum, DayGlo, sunGlo, UV, or UVA are not the same thing. I'm putting a
lot of emphasis on this because it's crucial to your turtle's health. Without
this light, Metabolic Bone Disease (MBD) will develop because your turtle won't
be able to produce vitamin D. Vitamin supplements are not a good replacement for
the proper lighting. MBD causes a very slow and painful death.UVB bulbs must be
replaced every six months as they lose their effectiveness after that, even
though they may still look fine. Light that comes through a window isn't
sufficient because the glass filters out most of the rays turtles need to stay
healthy. To prevent MBD, turtles also need calcium. The easiest way to provide
it is to place a cuttlebone in the tank. Cuttlebones are sold in bird
departments of pet stores.

Filtration

Turtles are very sensitive
to water quality. Even if you change the water every day, it can still contain
harmful chemicals. A good filtration system is essential. Water changes are also
needed even with a filter. If the tank is too small, no filter can keep up with
the amount of waste that turtles produce.

Feeding

Feeding is an
area where pet stores often give out bad information. Commercial food should
make up only 1/4 of the diet. Animal products (cooked meat, earthworms, canned
cat food) should make up another 1/4. The remaining half should be plant foods
(dark lettuce like romaine, bits of strawberry or melon, etc.). Hatchlings
should be fed every day. Older turtles should be fed 3 times per week.
Overfeeding can lead to gout and kidney failure.

For Further
Reading

This is among the most reputable sites on
turtles.


http://www.austinsturtlepage.com/Care/caresheet-red_ear_slider.htm

http://www.austinsturtlepage.com/Care/cs-yellowbelly.htm

Please hit reply for further help.

Joan