I'm sorry you lost your beardie, that's never easy to go through, no matter how old you are. He's out of pain now...
I know you're only 15, but you are old enough to understand and comprehend, and you must be an animal lover, you came on here for help when you had nowhere else to go, so I'd like to offer you a little advice if you'll listen...
The most responsible thing that you can do as someone who cares about animals, especially reptiles who have special environment needs to just even survive, is to make sure that you have EVERYTHING he needs in his environment before you get another pet. I'm sure that makes sense to you, it wasn't your fault that you didn't have a proper setup for your beardie, but you can take control of the situation now, before you get another beardie or any other pet...
For example, you mentioned that he had a basking light, but I'm assuming he had no
UVB light at all. Now if I was only able to buy one thing for my beardies, I'd buy them a proper
UVB light and fixture, either a Mercury Vapor Bulb (all in one bulb) or a long, flourescent tube
UVB light made my Reptisun and a long flourescent fixture for it. A proper
UVB light is the most important thing you need to buy for a bearded dragon, much more important for them than most other pet lizards because beardies are from the desert and need at least 14 hours of
UVB light every day in order to make vitamin D3, to absorb any Calcium they are given, to process any nutrition from food, basically they need a proper
UVB light to grow and continue to live. Without a proper
UVB light beardies have their growth extremely stunted, they stop eating, they start having twitches and spasms, they become paralyzed in first their back legs and then the front, they starve and become extremely skinny, and then they die. The worst part is that they can stay alive without a
UVB light for a year or more, during which they suffer horribly before they die. All of the huge, long, fat, active, healthy beardies you see online and in YouTube videos have a great
UVB light and replace it every 6 months or a year, whichever it calls for, because UVB lights stop emitting UVB after usually 6-8 months even though they still turn on and light up.
So please make it a necessity, your #1 priority that before you get another beardie or any other reptile or amphibian that requires a
UVB light (do your research first!) that you first come back on here and ask us what UVB bulbs and fixtures are appropriate for bearded dragons, and we'll not only tell you what UVB lights are good for beardies (there aren't many even though they say they're good for beardies on the box) but we'll also give you the cheapest places to buy them! And that goes for anything else that you need to get before you get another beardie, please come back here and ask us what you need to buy BEFORE getting another beardie, we'll be so happy to help you because we want people to make their new bearded dragon's environment healthy for them. The other criticisms I would give you (without actually asking you specific questions or seeing photos of your setup) regarding your bearded dragon enclosure and setup are #1 a 25 gallon aquarium is not nearly large enough for a subadults or an adult bearded dragon, a 20-25 gallon tank is only good enough for a bearded dragon until maybe up to 6 months old, beyond that age its way too small, and 6 months might even be to old for that size. I always start out buying the enclosure for a reptile that is the correct size for them as a full-grown adult. So a bearded dragon at the very, very smallest needs a 40 gallon breeder tank, and I really don't like to even keep them in those for longer than a year old, but I do know some people who use a 40 gallon breeder for their adult beardies and they say it works. So figure that before you get another beardie that getting a 40 gallon breeder tank is a must...Though if you get a baby or very young juvenile, and you can only buy limited supplies before getting the beardie, you need to buy a proper
UVB light and use your 25 gallon aquarium, but only if you're absolutely going to replace it with at least a 40 gallon breeder tank before he turns 6 months old...
Also, absolutely no wood chips, mulch, bark, Coco husk, Eco Earth, crushed walnut shells, any type of sand, or any other loose substrates for a bearded dragon ever! They can easily become badly impacted, which can cause permanent paralysis or can kill them, and also any of these loose substrates collect and hold in bacteria, fungi, and parasites/worms, all of which will make your beardie very sick and need a vet for medications. You only want to use solid substrates with a beardie like floor tiles from Lowes or Home Depot, Non-adhesive shelf liner, or newspapers or paper towels which can be thrown out and replaced whenever they get soiled. Easy, clean, and saves money!
One more thing, almost as important to bearded dragons as a proper
UVB light are proper temperatures inside their homes. Another reason a 25 gallon aquarium is a bad size of enclosure for a beardie is it is too small to establish a proper temperature gradient inside so that your beardie can have both a hot side and a cool side for comfort and for basking. If a bearded dragon has improper temperatures inside its enclosure it cannot properly digest it's food, and then they won't absorb their nutrition, and they can actually end up passing whole insects in their poop and can become impacted. Those cheap, round, stick-on thermometers that everyone has in their tanks because they come with kits are complete garbage(NEVER EVER WASTE MONEY ON A BEARDED DRAGON ALL-IN-ONE KIT, THEY DO NOT COME WITH PROPER LIGHTS OR ANYTHING ELSE). Those round thermometers are usually off by around 20 degrees in either direction, so you are either cooking or freezing your beardie without knowing it, plus you cannot measure the basking spot temperature with one of those, and this is the most important temperature. A really great thermometer that costs no more than those round stick-on thermometers that don't work are the digital thermometers that have a probe on a wire. Petco and PetSmart sell them for about $9, either their brand or Zoomed makes the same thing in yellow for the $9. You can actually place the probe right on the basking spot and get the temp, and they are very accurate.
Those are the most important things I see that you need to do before getting another beardie for sure, or if you're thinking about any other type of reptile or amphibian then you'll need to come back and do your research on whatever specific pet you're planning on getting, and make sure you have absolutely everything that is necessary for your new pet to be happy and healthy. We'll help you with anything we can.
I hope you take the time to read this post, as the main reason I'm taking the time to point out the absolutely necessary things that you must buy before getting another beardie is because I'm hoping that this approach will actually get through to you.
We see young kids and teenagers on here ever day with sick beardies and they are looking for help to save them because they really do love them. We typically find out very quickly that the reason their beardies are sick is because they don't have a proper
UVB light or any
UVB light (most common cause of illness and death), or they are not feeding them a proper diet at all, or they are on a loose substrate that has caused a horrible impaction or internal bleeding, or they have never given them a Calcium or multivitamin supplement. And even though we know what they need to do to get their beardie healthy again, and maybe they already know as well, because they are young kids or teenagers with no money they cannot buy any equipment that is 100% necessary for a beardie, or any food, or pay for a reptile vet. And unfortunately their parents or guardians refuse to help them.
It's very hard to not get mad at the parents in this situation, because they are the adults that not only allowed their kids to get a pet in the first place, but they ultimately are the people responsible for the pet.
Your father, for example, bought you a bearded dragon as a present. Okay, that's very nice of him, and I'm sure you guys most likely had an agreement that you would be responsible for taking care of your new pet, like cleaning his tank out, feeding him every day, turning his lights on and off every day, spending time with him daily, etc. And that's fine, as at 15 years old you absolutely can be responsible for a bearded dragon's daily care. However, you cannot be financially responsible for any pet's care at 15 years old, and your father, as the adult who bought you the pet as a gift, is 100% responsible for making sure that this living creature he brought into your home and family is financially taken care of. And probably 98% or more of the kids that come on here for help actually have ZERO support from the very parents that allowed them to get the pet or even bought the pet for them.
Right from day one your father said you could have a bearded dragon, yet he refused to buy him any
UVB light, the absolute most important item a bearded dragon needs. This makes no sense and is just horribly frustrating for us, but most of all for you! I could tell in your original post that you knew having no
UVB light, wood chips as a substrate, having a 25 gallon tank, you knew all of this was very bad for a beardie, but there wasn't a thing that you could do about it, and I'm so sorry that you were put in that situation. That's why I'm proposing to you that YOU AND ONLY YOU take responsibility and control of any of your future pet's lives.
If saving up $70-$80 for an all-in-one Mercury Vapor Bulb, $9 for a digital probe thermometer, $50-$100 for a 40 gallon breeder tank (always check Craigslist for a 40 gallon breeder or a large EXO Terra first), and if I were you I'd also save an extra $100-$200 in advance for ordering bulk crickets, or better yet dubia roaches so you can start your own colony and always have free food, if saving all of this money up BEFORE YOU GET ANOTHER BEARDIE takes you 6 months to a year, or longer, however long it takes you, then that's how long it takes you to get another beardie. That's my proposition to you, because you're a responsible young adult (you took the initiative to come on here for help), you'll soon be 18, and I hope I and every other member of this forum have really impressed upon you how important it is to not purposely take responsibility for another living creature until you are in a position to do so. I figured out a long time ago (I'm 37) that when the adults in my life that were responsible for me failed to do what they should have done for me as a teenager, that meant I had to just stand up and do it for myself. And being responsible for another living creature is not to be taken lightly.
Again, I'm so very sorry that your beardie passed away the way that he did. I hope you have a lot of good memories of him, and I'm sure that whenever the time comes for you to get another beardie you'll be wiser and fully prepared and educated first. We are always here so please ask any and all questions, send private messages, whatever you need we will do our best to help you.