Please feel free to message me any time, it's not at all unusual and actually is the norm that when 2 dragons are housed together that one thrives and one is stunted, has nutritional deficiencies, and often dies. What humans don't understand is that we as people cannot at all "see" what is going on inside a tank with multiple dragons inside it. I can't tell you how many heated discussions I've gotten into, both in person and online, with people who are housing 2 or more dragons together (both males with other males and males with females too), and who have 1 dragon that is healthy, growing, and perfectly fine and the other is stunted, less than have the size of the other dragon, sickly, no appetite, etc., and they absolutely insist that they will not separate them because "That's not the problem at all, they get along fine", or "They love each other, they lay on top of each other to sleep", or "I'd be afraid to separate them, they'll become depressed and lonely"...yet they cannot find any other explanation for why 1 dragon is thriving and the other is dying...
What we physically "see" inside a tank with 2 or more dragons is not at all what it appears to be. People tend to think in a very "superficial" way, meaning they only see what is visible on the surface, and they think of their pets in terms of how human beings interact with each other. Of course if 2 human beings are constantly laying on top of each other, lol, then they probably like each other, and if they don't it's illegal and the one on top is going to jail
However, we just can't look at animals that way. What is really going on in that dragon tank is one is laying on top of the other because either the one on top is dominating the one on the bottom, or even worse, the one on top is the submissive dragon, and is actually being forced to lay on top of the dominant dragon on the bottom. What we cannot possibly see is that the dominant dragon gets all the best insects (scarfing up the largest ones, or the ones that look best to them), all the best veggies and greens out of the bowl, and most important to their growth and development, the dominant dragon is sure to be constantly sitting in the best places for the strongest UVB/UVA/UVC exposure, the best temperatures for nutrition digestion and absorption, etc. And we also don't see that at certain times of the day, there are better types of light rays and temperature ranges for them to be sitting in than at others, and that's where the dominant dragon will always be. There are very purposeful reasons that dragons go to the strongest area of
UVB light and highest basking temperatures directly after they eat, and then later they go to the spot with the most intense UVA light, or the coolest temperature areas, etc. There are very deliberate reasons that they go to certain areas at certain times, and you can be sure that the dominant dragon being in certain areas of the tank at certain times of the day is completely purposeful. So it's not simply a matter of the larger, healthy dragon eating more food and growing larger, it's a matter of the larger, healthier, dominant dragon in the tank taking the best of everything at all times...
Yes, please move their tanks into separate rooms ASAP, I honestly wouldn't worry about the temperatures too much, as long as each tank has a proper bright-white Basking Bulb that keeps that tank temperature zones within the correct ranges then it's fine, right now the most important thing in aiding the recovery of your "unwell" dragon is getting the source of her constant stress away from her. As long as she knows that the dominant dragon is nearby her, and she has no way of getting away from him, she is feeling just as stressed out (and it's constant) as she was when he was inside the same tank as she was in. She's still going to feel like she is NOT ALLOWED TO EAT, NOT ALLOWED TO BASK, and NOT ALLOWED TO DO THE THINGS SHE NEEDS TO DO TO GET HEALTHY as long as that other dragon is nearby and she can smell him, hear him, etc. For all she knows he can just walk right back into the tank at any second. So this is still causing the same extreme, constant stress that she's been feeling forever. Once he's out of the room completely, she will no longer be able to smell him (or at least smell him in the way that she knows he's still in the room), she won't be able to hear him or see him anymore, she'll know that he's gone, and only then will she feel like she's able to eat, bask, and live the way she needs to...so yes, get them in different rooms immediately!
I'm a huge believer in this theory, and the only reason I am is because I see the results time and time again. I'd be willing to bet my life right now that within a couple of days of you moving the dominant dragon out of the same room that the other dragon is in, she will start to attempt to eat more, bask in the places she needs to bask in, move around as she wishes, sleep when she wants to sleep (and sleep soundly), etc. Once she does these things without any repercussions from the other
dragon, and once she does these things and she still no longer smells him, sees him, hears him, etc., and she's sure he's completely gone, only then will she relax and start to live the way she needs to live...Think of it like an abused spouse or abused child. Once the abuser is arrested and put in prison, the abused spouse or abused child doesn't automatically just start living normally again, or living the way they want to...we say that they're "Gun-Shy", and that's exactly the same thing that's going on with your dragon, she's Gun-Shy. Only once an abused person is certain that they can do certain things that they want to do (things that their abuser would hurt them for before he was arrested and taken away) without their prior abuser coming back to stop them as they used to, only then will they start to feel comfortable living their lives the way they want to again...This is the best analogy I can come up with for what happens when Solitary Animals are forced to live together in a small cage or tank and domination occurs.
Please don't think that I'm blaming you or scolding you for housing them together, I'm not at all, I'm just trying to thoroughly explain what's still going on with your dragon. So often people are given horrible advice by everyone from the dragon's Breeder (yes, many "reputable" breeders, dragon breeders who are very well-known for producing expensive, exotic morphs and colors have gotten by with a lot of luck and poor husbandry), Pet Shop employees (probably the worst), and online forums and message boards that are supposed to be full of "knowledgeable bearded dragon owners. It becomes so difficult to know who to believe, and why wouldn't you trust a Pet Shop employee who takes care of these creatures, or their actual Breeders!
I actually had a teenage girl (she said she was 14) come on this forum about 6 months or so ago and really get me upset, I had to check myself and just blast her with facts and citation links that she could follow to see that she was very incorrect in what she was saying...It was a post written by someone who was having the exact same issues as you are having, and they resulted from exactly the same situation: The OP had 2 dragons housed together in a 40-Gallon Breeder Tank, a male and a female, they were housed together from a month old (she bought them both at the same time from Petco I believe, and of course the Petco employee, wanting to sell 2 dragons and a big tank, lights, etc. told her that she could house them together for the rest of their lives with no problems). And at the age of 8 months, the male dragon was a big, beautiful dragon, already 16 inches long, plump, active, and eating like a garbage-disposal, while the poor little female had hardly grown or developed at all, she was only 9-10" long, extremely skinny, very lethargic, never wanted to eat, never moved around, and just slept all day long. The OP assumed that she was "sick" with parasites or an infection of some kind, and the very first reply written was not by me, but whomever wrote it immediately told the OP that the problem was that she had housed them together and one was dominating the other, and that they needed to separate them immediately,. and get them into different rooms so that the unwell dragon could feel safe and relax. The OP was doubtful because the Petco employee had "seemed very knowledgeable" and she believed him, so I then wrote my reply, explaining that Bearded Dragons are naturally and innately Solitary reptiles, who in their natural habitat in the Australian Desert live completely alone, and the only time ANY dragons in the wild come together are when a male and a female come together to mate, then they immediately separate, the female lays her eggs and leaves them, the babies hatch and take off alone, etc. Well the next reply was this 14 year old teenage girl, who at first I assumed meant well and was just misinformed, but unfortunately she was rude, nasty, and totally unwilling to educate herself by reading any of the journal articles, magazine articles, or even the Wikipedia page on Bearded Dragons, lol. She made a reply, out of nowhere (I don't believe she had ever posted before this on the forum) which stated that "You're completely wrong, Bearded Dragons are not "Solitary" reptiles at all, they are "Pack Reptiles" that live in groups of 4 or more at all times, and are extremely social all the time in their wild environments, sharing all food, water, and housing, they travel together all the time, they are never alone, and they brumate together during the winter. You will never, ever see a wild Bearded Dragon by itself, they are always in "packs" of at least 4 or more, usually you see "herds" of them, and it's actually very cruel to only buy 1 single Bearded Dragon as a pet and house it alone, if you aren't going to buy at least 2 dragons to keep in the tank, then you shouldn't get any at all because it's very, very cruel to keep them alone"...I'm paraphrasing her reply, but I'm pretty close to exactly what she wrote...
My only problem with response like this on the internet, no matter where they are written, is no matter how ridiculous the comments are, there is always going to be at least 1 person who is doing research on Bearded Dragons that will come across that comment and believe that 14 year-old teenager rather than believing the other 30+ experienced Bearded Dragon owners who replied to her ridiculous comment and who made it very clear to her that what she was saying is completely false, and here are the links to proof that you're wrong...For whatever reason, at least 1 person will believe that teenager's comment, and that's at least 1 baby bearded dragon who is going to be housed with multiple other dragons and who will most likely end up dead, and the poor owner (who is also a victim in this scenario) will have no idea what they did wrong...that's why you must find multiple sources for your information, and make sure that they are credible sources that are reliable and have credentials...
Sorry for the long story, but I think it's an important message, and if only 1 person doing research reads this and changes their mind about buying 2 dragons and only gets 1, then I've done my job...