The short course on water dragons....
They need a UVB linear/tube light (NOT A COMPACT...they cause eye problems). There should be no glass or plastic between the light and the dragon. Sunlight is the best source of UVB but most people can't put their dragons outside. Exposure to UVB allows the dragon to produce D3 which allows it to use the calcium in its diet.
Most feeder insects have a poor ratio of calcium to phosphorous so I dust the insects before feeding them to the dragon at most feedings with a phos.-free calcium powder.
I also dust twice a month with a vitamin powder that contains a beta carotene source of vitamin A. Beta carotene can not build up in the system like preformed can. Excess preformed vitamin A can prevent the D3 from doing its job and lead to MBD,
Since my dragons don't get sunshine, I dust twice a month with a phos.-free calcium/D3 powder lightly. D3 FROM SUPPLEMENTS can buid up in the system so don't overdo it.
The basking temperatures should be in the high 80's to provide enough heat for proper digestion.
The dragon (depending on its size) can be fed an assortment of insects (crickets, superworms, (once in a while) waxworms, silkworms, etc.). They should be well fed and gutloaded. You can gutload the crickets with an assortment of greens (dandelion, kale, collards, endive, escarole, mustard greens, etc. and veggies (carrots, squash, zucchini, sweet red pepper, sweet potato, celery leaves, etc.)
The dragon can be fed those same greens and veggies as well as a bit of fruit (apple, pear, melon, berries, etc.)
A water container large enough for the dragon to fit into completely but not deep enough that it can drown should be provided too. The water should be changed every day or two.
Hope this helps!
(BTW...I have been keeping/breeding/hatching/raising dragons for over 15 years.
