The final 2 additions to my tank for a while ID

That would be a scooter blenny, a member of the dragonet family and requires a VERY mature tank with lots of copepods like any other mandarin. Not to rain on your parade, but I give it 30 days to live in your tank unless you plan on buying $60 in Reef Nutrition Tiggerpods every week. Actually, looking closer at the bigger picture, I give it 2 weeks because it is already a "goner" by looking at its sucked in tummy. With dragonets you must look very closely at their belly to make sure they are fat and healthy. If you get one already skinny they are usually on their way out.

Ya, that is a leather, normal to be closed up when first put in.

Just so you know, dragonets like you got, if given the chance, will eat a copepod every 5 seconds the entire time they are awake. Most mature tanks usually can not keep up with that type of consumption. I hate that LFS sell those fish so often and so cheaply, and call them gobies or blennies to the unsuspecting victim. I was guilty myself of getting that same fish when I first setup my tank, didn't last 3 weeks.

No, really no point. At your LFS it is going to die anyway. You have a better chance of having it survive then they do. If you can get some Arctipods or something like Cycops/Cyclopeez and some bloodworms (dragonets seem to love bloodworms, they just are not healthy so use them as a snack) and see if you can get him to eat ANY type of frozen or prepared foods. If you can, your doing better than 90% of dragonet owners right there.

I had no idea and no one told me what to feed them so mine just wasted away. Now I know at least what foods they eat and what "prepared" foods they are known to go after on a few of them, so giving you that information will greatly increase its chances in your tank. I would say probably a 0-1% chance it will make it to the end of the month at your LFS... right now not knowing what foods it will eat, I say your at a 10% chance of survival now, but if you can find some foods like I mentioned and it will eat them, your chances will skyrocket that it will make it. I would take action ASAP to get some of those foods though because he is already in "starvation" mode from the picture.

Copepods do help clean up the tank but they are a food source for many fish as well. There is no way a fish can eat them all because they hide in the rocks and sand most of the time and come out at night. A mandarin will really put a huge dent in their population though in a short time. If at night you see your glass covered in "bugs" now, within a week you won't really see any.

I would highly recomend articpods. I have been using them for a while and everything in my tank loves them. I put some in nightly and all my fish have plumped up. Now when i but anything new I have my LFS put some in the tank to make sure it eats. My LFS uses it for tthier own fish.

Once in starvation mode, unfortunately, there is really little else you can do. Even buying the supps discussed by Ace the little fella is gonna be a goner. I had the chance today for a free, yep I said free, mandarin... had to let it slide because (1) my tank is not mature enough, not large enough, and (2) he was lookin' a bit thin.

It sux, I know, but it is something to be aware of, and mindful of. Not to preach, but really you shouldn't buy a fish unless you know all about it (or have lots of money and remarkably clean Karma). You seem very dedicated to doing this right regardless of cost... please extent that passion to your selection of fish.