There are a few husbandry issues which may need to be addressed which may be responsible for Nemo's symptoms:
1.You may or may not have issues depending on the gender of your dragons.If one of them is a female, then the male can over-breed her which means that she can become calcium depleted if/when she lays eggs.Females can lay eggs without the presence of a male because they can store sperm; so even if separated, she could continue to produce eggs.
In addition, bullying issues can occur and injuries be seen even between two males or females from the same clutch.
So, for now at least, I would suggest that you separate them but this LINK may help in sexing Nemo.
2The next issue to address would be the substrate.Walnut shell can be dangerous as can all loose substrates since it can be ingested and potentially perforate the intestinal tract
Alternate suggestions would be tile, cage carpet, slate or even paper.I would avoid sand since it can cause skin problems and corneal ulcers.
3. Temperatures and bulbs:The basking area should be between 105-110 degrees Fahrenheit; the warm side in the mid-90’s and the cool side of the tank in the 85 degree range.These ranges are important for digestion and passing of stool.
I also recommend two lights—a daytime basking bulb as well as a UVB light.
I like the Reptisun 10.0 florescent UVB tube since it can help prevent Metabolic Bone Disease (a real concern in dragons) since it works in conjunction with calcium to avoid this problem.
The UVB needs to be changed every six months.
4.The diet may also need to be modified somewhat. A dragon over the age of one year needs 80% veggies and 20% live prey. Appropriate veggie options include: Collard greens, mustard greens, dandelion greens, escarole and curly endive. Butternut squash and various berries are great for a treat.
The veggies should be supplied fresh daily and offered about an hour after the lights are on.
Live prey should include crickets, silk worms, roaches, goliath worms and phoenix worms. Canned prey looses its nutritional value and is high in chitin which is in the outer shells and can cause a blockage.
All veggies and prey should be dusted with calcium daily 5 days a week and vitamins 2 days a week. This LINK also provides a number of other options to consider.
As to how you can help Nemo now, the following are my suggestions:
A warm bath soak of 50/50 water and Dioralyte to which you have added some calcium for 20 minutes. Dragons can absorb fluids through their vent areas.
You can mix some baby food with the calcium powder and try to feed with a syringe by dropping a small amount on the snout and hopefully Nemo will lick it off.
It wouldn’t be bad idea to have Nemo examined by a herp vet if there’s no improvement within a few days. Internal parasite issues may also be causing Nemo's symptoms. If you don't have a good one, this LINK and this LINK will help you locate one.
I hope this helps and, again, my apologies that it's taken so long for you to receive an answer. Deb