Hi, and welcome...You've got some serious husbandry issues, and I hope you'll listen to us because your dragon does look a bit small for being 7 months old, and he's not properly digesting his food due to inadequate UVB/UVA lighting, improper temperature zones, and an inadequate diet. The most serious issue here is the inadequate
UVB light, as Bearded Dragons need 13-14 hours every single day underneath strong, appropriate
UVB light that is reflected throughout their tanks, and your dragon has not gotten this, presumably ever. So his growth is a bit stunted due to this most likely, he's not able to digest his food properly, and he is no doubt starting to suffer from the typical calcium deficiency, which will soon start the MBD in-motion.
First of all, an easy fix is to completely stop feeding him the mealworms. First of all they are extremely high in fat, very low in protein, very low in vitamins and minerals that Dragons need, and most importantly they are mostly just hard, chitlin shell that Bearded Dragons cannot properly digest. So that comparison you made about his poop not having whole crickets in it, but since you have started feeding him the mealworms you've seen chunks of the shell in his poop, was a very wise comparison to make, though it's not due to anything other than the fact that Dragons just cannot digest mealworm shells properly, and even if they could the mealworms will only cause malnutrition and nutritional deficiencies, Fatty Liver Disease, and chronic bowel impactions. No doubt the improper temperature zones are probably causing a little of this issue, but even if your Basking Spot Surface Temperature is perfect (between 105-110 degrees F maximum) he still cannot properly digest them, and you really honestly don't want him to because they are not a healthy staple feeder for Dragons. They're great for certain reptiles, like some geckos and such, but not at all good for Bearded Dragons. So just stop the mealworms and you'll save yourself and him a lot of future trouble and expense. Stick to either crickets, any of the adequate species of roaches, Phoenix Worms/BSFL, or Silkworms. BSFL/Phoenix Worms are one of the healthiest daily staple feeders for Dragons, so if you want to switch to a worm for him, start ordering size Large BSFL/Phoenix Worms online from a place like
http://www.dubiaroaches.com or
http://www.symtonbsf.com I order 1,000 a month from the first place for $23 shipped, so they're cheap in bulk too. They are low in fat, high in non-purine based protein, very high in calcium (you still have to dust them in calcium 5 days a week and in a multivitamin 3 days a week like any other feeder insect), and they are also full of
hydration.
Your major issue is your compact/spiral
UVB light, which is only 13 watts and totally inadequate for a Bearded Dragon, who needs strong
UVB light for at least 13 hours a day. Combine that with the fact that you have the already far too weak
UVB bulb sitting on top of a mesh lid, which is then blocking 40% of the already inadequate
UVB bulb, and your dragon is getting basically no
UVB light at all. This is not optional, you absolutely must get him an appropriate UVB TUBE and a tube fixture for it that has a reflector inside it, and you must be sure that you get it mounted correctly and within the correct distance of his basking spot/platform based on what strength of UVB tube you buy. There is only 1 compact
UVB bulb that is strong enough for a bearded dragon, it's an Exo Terra 200
UVB bulb that is 26 watts (versus your current
UVB bulb that is 13 watts, so you see the problem), however, because you have a nice, appropriately large tank for your dragon, as most do, it's extremely difficult to get adequate
UVB light throughout the large tank with a compact
UVB bulb, even a 26 watt one. You have to mount it inside the tank (under the lid) in a special Nano Hood that reflects the
UVB light throughout the tank. In my opinion, and most other experienced Dragon owner's opinions, it's just not worth it, and it's not very reassuring that the dragon will get adequate
UVB light. That's why 98% of experienced Bearded Dragon owners and breeders use long, fluorescent UVB tubes inside of long tube fixtures which have a metal reflector behind the UVB tube so that adequate
UVB light is reflected throughout the large tank/enclosure.
There are 2 different strengths of UVB tubes: The much stronger and more appropriate T5 strength, and then the much weaker and more restrictive T8 strength. You can successfully use a weaker T8 strength UVB tube, however the entire tube fixture that it's inside must be strapped to the underside of the mesh lid of the tank, as the T8 tubes do not emit a strong enough
UVB light to deliver adequate
UVB light to the dragon on the other side of the mesh lid. Also, the much weaker T8 UVB tubes must be within at least 6" of your dragon's basking spot/platform, so if you have a tall tank this can be more difficult. Lastly, the T8 UVB tubes must be replaced once every 6 months on the dot, as they have a very fast UVB decay-rate, and at 6 months old they are no longer emitting any
UVB light, they will still turn on and light up, but no
UVB light is emitted. For these reasons most of us use the much stronger and more appropriate T5 UVB tubes, and they save you money as they only need replaced once every year, as their UVB decay-rates are much slower.
The much stronger T5 UVB tubes are strong enough to sit on top of the mesh lid and still deliver adequate
UVB light to your dragon, JUST AS LONG as there is no clear, plastic cover over the tube fixture that is covering the UVB tube (some tube fixture come with a clear, plastic safety cover attached to the bottom of the fixture, and over the UVB tube inside the fixture, and NO
UVB light at all can penetrate any type of glass or plastic, it blocks 100% of
UVB light), AND as long as your dragon's basking spot/platform is within at least 10-11" of the UVB tube. So the stronger T5 UVB tubes give you twice the leeway on the height of your tank and basking platform. And again, the T5 tubes only need replaced once a year.
******FYI, DO NOT BUY ANY UVB TUBES MADE BY THE MANUFACTURERS ZILLA, ALL LIVING THINGS, REPTILE ONE, OR TRIXIE....All of these brands (there are others, but these are the most common that are sold at Petco and PetSmart) emit harmful light rays that always seem to cause eye damage, blindness, and severe neurological damage to Bearded Dragons. You can search for "Zilla", "All Living Things", and "ReptileOne" UVB Tube in search bar in this forum and read the hundreds of posts regarding these brands not only causing severe health issues, but also being much weaker in
UVB light than the higher-quality brands, and they often result in MBD anyway.
The 2 brands that most experienced owners use are Reptisun 10.0 (not the Reptisun 5.0, as they only emit 5%
UVB light and have to be much too close to a Bearded Dragon than is safe for their eyes and skin), and then the brand Arcadia. Both of these brands make both a T8 strength UVB tube and then also at least one T5 strength UVB tube (Arcadia makes 2 T5 strength UVB tubes, one that is a 12% tube and one that is a 14% tube, both are awesome and adequate for Bearded Dragons, the 12% is fine for a 40-gallon Breeder tank or even a 4'x2'x2' enclosure).
Most pet shops don't sell the T5 UVB tubes, you have to order them online, they only sell the weaker T8 tubes, and the much weaker and shorter T8 tubes cost double what the stronger T5 tubes cost online, so that's kind of a no-brainer. You can buy an 18" Reptisun 10.0 UVB tube at any Petco or Petsmart for $37.99 a piece, just for the tube, and then buying a fixture for it will cost you probably around the same amount of money, around $40 in either store, which is ridiculous. The only Reptisun T5 strength UVB tube that I know of that is sold in any Petco or Petsmart is part of a package deal that includes both the UVB tube and a Hood for $60, HOWEVER, THE REPTISUN T5 UVB TUBE THAT IS INCLUDED IS ONLY A 5.0 OR 5% TUBE, AND IS NOT ADEQUATE AT ALL FOR A DRAGON, SO AVOID THAT PACKAGE DEAL!!! Many people mistakenly buy this $60 package deal because they think it's a good deal, but the 5.0 tube cannot be used in that hood and set on top of the mesh lid, and it would have to be within about 3-4" of your dragon, which is too close to be safe for his eyes.
So your best bet is ordering online, as you can buy a 22" Reptisun 10.0 T5HO UVB tube on Amazon.com for about $24 shipped! And they also sell one 24" fixture, rated for a T5 tube that is 24 watts, and that includes a reflector inside it, for about $28 shipped. So you can get one of the best UVB tubes available for a Dragon and a fixture with a reflector for it for under $60 shipped on Amazon.com. That's what I highly recommend you do, either way you must get your dragon under a proper UVB tube ASAP, before the MBD starts setting in.
As far as temperature zones go, I'm glad you have a probe thermometer, please make sure that you are ALLOWING THE PROBE TO SIT ON THE SPOT YOU ARE MEASURING FOR AT LEAST 20-30 MINUTES BEFORE YOU READ THE TEMPERATURE!. Otherwise the Probe will not have been allowed to heat-up to the actual temperature, and the reading is worthless.
BASKING SPOT SURFACE TEMPERATURE: Between 105-110 degrees F maximum. ***110 degrees is the maximum Surface Temperature that should occur inside a Bearded Dragon's tank.
HOT SIDE AMBIENT (AIR) TEMPERATURE: Between 88-93 degrees F maximum. ****93 degrees is the maximum Ambient/Air Temperature that should occur inside a Bearded Dragon's tank.
COOL SIDE AMBIENT (AIR) TEMPERATURE: Between 75-80 degrees F maximum.
***Double check all 3 temperature ranges using the Probe, being sure to allow the Probe to sit on each spot for at least 20-30 minutes before reading the temperature.TO PROPERLY MEASURE THE AMBIENT/AIR TEMPERATURE WITH A PROBE THERMOMETER: Use the Suction Cup that came with the Probe Thermometer and place it on the wire right below the Probe. Stick the Suction Cup to either the front or side glass of the tank on the Hot Side of the tank, about 2" above the floor, and let it sit for 20-30 minutes, then read the temperature. Then do the same on the Cool Side of the tank, stick the Suction Cup to either the front or side glass on the Cool Side of the tank, about 2" above the floor of the tank, then let it sit for 20-30 minutes. Then read the temperature.
****Also, you should never use any colored bulbs for a Bearded Dragon, only bright-white colored bulbs, as you are trying to replicate natural sunlight as closely as possible. Bearded Dragons see in full-color, just like we do, and using a red, blue, green, purple, black, etc. bulb as a basking bulb confuses night and day for them, masks their food, and just does not replicate natural sunlight.
I don't know if that red bulb is your regular, daytime Basking Bulb or a nighttime bulb, but either way you need to throw it out. If it's what you are using as his daytime Basking Bulb then this is very unhealthy and needs to be replaced immediately with either a Reptile Specialty Basking Bulb that is white in color, like a ZooMed Intense Basking Spot Bulb, or what most of us use that is cheaper are just the regular, household, Halogen Indoor Flood Bulbs that you can buy at Walmart, Lowes, Home Depot, etc.
If that red bulb is a nighttime bulb, please stop using it, as it's totally disrupting his sleep. Dragons comes from the Australian Desert, which is both Pitch-Black and very Cool/Cold at night, and as such you need to allow your dragon's tank to not only be Pitch-Black at night with absolutely NO lights on at all of any color, but also his tank needs to be considerably cooler than any of his daytime temperatures in order for his body to be able to rest properly and soundly.
****As long as your dragon's tank is at least 65 degrees at night (meaning your house would have to be 60 degrees or colder at night for his tank to drop below 65 degrees at night) YOU NEED ABSOLUTELY NO NIGHTTIME HEAT SOURCE AT ALL FOR YOUR DRAGON, AND HE WILL SLEEP MUCH MORE SOUNDLY AND COMFORTABLY AT NIGHT! Most people who own dragons need no nighttime heat source at all because most people keep their homes at or above 60 degrees at nighttime. If that's the case, which it probably is, then just turn out both his UVB and his bright-white colored basking bulb off at night and that's it. *****If you like to freeze yourself at night for some reason and your house is kept below 60 degrees at night, which I doubt, then all you need is a very, very low-wattage Ceramic Heat Emitter bulb (CHE) that will put his tank temperature between 65-70 degrees maximum. So you're talking a CHE that is like 10 watts. 80 degrees is too hot for a Dragon's nighttime temperature.
I've posted a picture of his set up and lights
