Thank you for getting back to me. I suspect that you got your information on care from pet store personnel. Unfortunately, such information is often inaccurate. While pet owners should be able to rely on pet stores, the staff there is often not well-informed. The stores are in business to sell things, not to ensure the animals’ health. Many reptiles die each year because of it. You have been given some of that incorrect information.
The cold temperatures have almost certainly contributed to the lethargy and appetite loss. Normally, you’ll want daytime temperatures between 84* and 88* F (29*C to 31*C) and night time temperatures between 75* and 80* F (24* and 27*C). Sometimes being just a little too cold can lead to problems over time. The under cage heat mat is not the best way to provide heat for a water dragon. They do much better with heat from above. You may have to add a second light. If you live in an area that has farm stores, you can buy a clip-on 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 and home improvement stores sell similar light fixtures as work lights. You can adjust the temperature by raising or lowering the light fixture, but don’t put it so low that your pet can be burned.
One thing you can do right away to help him is to make sure the temperature in the enclosure is kept at 85 to 90*F (29 to 32*C) day and night. While it's usually recommended that the temperature be lowered at night, when they're sick, it's better to keep them warm all the time. This link talks about that:http://www.triciaswaterdragon.com/ailments.htm
You may want to consider a different substrate. Bark tends to dry out quickly, and can lead to impaction if it is accidentally consumed. Water dragons need humidity at 80%. It’s difficult to keep it that high. After months or years of low humidity, it can have an affect on their health. Soil holds moisture much better. Live plants in the enclosure, misting several times a day, and keeping a solid cover over part of the top can all increase humidity.
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, daylight, UV, and UVA are NOT the same thing. I'm putting a lot of emphasis on this because it's crucial to a reptile’s health. Without this light, Metabolic Bone Disease (MBD) will develop because they 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 the UVB rays. I recommend the following website for information on care. It’s really like a whole book on water dragons. It is a reliable source of information by a leading authority.http://www.triciaswaterdragon.com/dragoncr.htm
You'll need to correct the conditions as soon as possible. I'll also give you a first aid measure to take. Buy some unflavored Pedialyte (yes, the kind for human infants). Prepare a shallow bath consisting of 1/2 water and 1/2 Pedialyte. Soak your dragon for about 20 to 30 minutes twice a day. Reptiles can absorb the electrolytes and fluids through their vents (where droppings pass out), so make the water deep enough to cover the vent. Be sure to supervise closely.
If the above measures don't help, it's likely that your dragon has actually become ill. In that case, you'll need to see a reptile vet. this link will take you to a directory of them:http://www.anapsid.org/vets/index.html#vetlist
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