Hello!
"Stress marks" is actually a misnomer...they are a natural coloration, and often darken or lighten according to the beardies level of excitement. They do sometimes indicate stress, but it can be good excitement (yay! more worms!) or fear ( "I do not like that big dog") or somewhere in between ("I want out for snuggles, now!). The marks tend to lighten up as they age, often disappear entirely by full adulthood, around two years or so. Each beardie is different, so watch yours and take note as to what event is taking place that makes him darken. It can be useful to know, as a communication devise. My girl has darker marks when she is unsure of something, or worried about her safety. She is less than six months old, and was terribly mistreated and starved ( very near death, sadly) in her first weeks, before I rescued her, so she is hyper alert about her safety and well being. My big boy, DeziLu, was never in danger, and never missed a meal, and has a very laid back disposition. He is also older, almost four years, and never has the marks at all anymore. He had them as a juvenile, but they vanished as he aged.
An increased showing of the marks can indicate something wrong--a health issue, or an environmental issue-- so I would investigate those closely, if my beardies suddenly started showing marks more than what is usual for them. Your beardie does not appear to have any health problems,and looks relaxed and happy, but with just a photo, it is hard to tell. Perhaps you could post some photos of Po and his viv set up, etc., if you want some feedback from the community.
The beard puffing while basking is also normal. Younger dragons, especially, puff more, as they discover their beards, and will sometimes puff to show off their newfound talent, to dislodge a bit of shed, to say hello, and just for the fun of it. However, a dark black puffed beard, Raised spikes, and stiff body may indicate extreme stress! Either serious fear, or big health problem, and should be taken care of quickly. If the mouth is also open, or teeth bared, be very cautious, as even the most docile fellow will bite if he is that upset. Dezi almost never puffed (I call it "bearding") but Penny puffs frequently, especially when she wants my attention, needs some hugs, or is in the mood for more food,which is just about always, at her age!
Aren't beardies adorable? As you learn your Po's special language--his facial ezpressions, tail positions, posture and little sounds) you will discover a whole new level of communication is possible. They can "tell" you what they need, or what is wrong. Miss Penny has finally discovered that she can communicate with me and get me to serve her better, and now she never stops! ha, ha! She was so silent and afraid when I got her, and now she is a regular chatterbox, in her beardie way! Dezi seemed to know from the start that he could communicate with me. He began training me right away. He is more the strong, quiet type, very subtle. But they are both total drama queens.
As you learn more and more of Po's unique personality, you will probably fall in absolute love with him, if you haven't already. They are such amazing creatures. It only gets better, as they mature.
If you have done your research, followed best advice for lighting, heat and nutrition, and give lots of love, attention and snuggles, your Po should be just fine....You sound like a fairly new beardie slave, and there is alot to learn--I am still learning, after four years! I was constantly on this site asking questions when Dezi was younger. There are some very kind, compassionate, helpful people on this site. Just keep in mind that not everyone has the same opinion, or the same experience/training with beardies. You know your beardie best, and what works best for you both. Looking forward to seeing more of Poe and his adventures! Here are my two beautiful, demanding, fabulous beardies. (as they all should be
)
Miss Penny still has trust issues, but loves snuggles and her human of choice. (yay, me!) She is my brave beauty.
DeziLu loves everyone, and everyone loves him. He goes with me everywhere. He is over 24", and +2lbs.! He is my gentle giant.