Black beard means they are not particularly happy at the moment. It's mostly a protest saying put me down. Once they realize you mean no harm they stop. :roll:
his beard turning black could also mean that he doesn't really trust you much so what you should do is interact with him more, hold him, pet him, and maybe just let him fall asleep in your hand,he will trust you more and will not turn black when you try and hold him, and also another way that you can check that he trust you or not (and I know this is a bit off topic from what you wanted to know but just so you can know.)when ever you feed him his veges. If he stops eating and turns around to see what your up to or if your going to try and hold him then that probably means the trust level is low, but if he just continues to eat and doesn't really pay attention to what your doing then that means he trust you enough that he doesn't have to stop eating to see if your going to do anything to him. :wink:
You can try putting a shirt you've worn in his viv with him to sleep on. And also holding him in his bath. Both have worked for me very well.
I hope this helps a little.
Good luck
I just set Swordtail's timer for his bath and paused it so I could actually fill his soaking bowl up and he crawled over my phone and canceled the timer
Mirage came out of brumation on April 26. He was doing great. On May 2 he started acting funny. We just redid his tank, and he keeps going into one of his hides. He just lays there. He shows no intrest in food. HELP!