This question is for a dog Veterinarian. I had a standard poodle named Carlos. Carlos was 16 years old. I am writing to get your opinion if you think we did the right thing. Ultimately, we chose to put down Carlos by euthanizing him. Here are the facts: Carlos was a 16 year old male poodle. From about 8 months ago, he started to lose the ability to stand and walk on his own hind legs. From my research, it seems like that was because of some type of spinal chord atrophy probably due to aging. So, the quality of his life was difficult at the end. We had to always bring him out to go pee, or bring him to his food because he was not able to do it on his own. Anyhow, Carlos was typically in good spirits and able to eat on his own, except, starting on November 1, 2021, we noticed that he very quickly turned lethargic, and he wasn't eating his food so easily. He was acting almost zombie like, and he couldn't keep his balance. I would listen to his heart over the next few days, and I noticed that his heart reduced to, and ranged from about 50-60 beats per minute. His normal heart rate was usually faster than that. His heart beat was also irregular. Sometimes it trickled down to a slower lub-dub, and sometimes it would speed up. Ok, so, then, around November 3, 2021, Carlos was lying down on the ground, and we noticed blood was leaking/seeping out of his buttocks area (not coming out of his butt-hole, but instead his butt Area). It looked like an internally bleeding bruise, and I guess his skin was so thin, that blood was leaking out. The blood had a pinkish, watery look to it. So, it was on November 3rd or 4th that I started to decide to get Carlos seen by a vet. So, on the morning of November 5th, we took Carlos to a vet. At this point, on November 5th, I noticed that it was even harder for him to eat, he was more lethargic than ever before, and I even noticed that the coloration of his penis turned to almost a pinkish-white. So, I brought Carlos to the vet on morning of 11/5/21, and I explained all of his symptoms to the vet: the bloody bruise/mass at his buttocks, he also developed some green discharge in his eyes, he was shivering (which he had been shivering for the last 2 or so months, probably due to old age), his penis had a pale color, and he was very skinny (and lost a lot of muscle probably due to inactivity due to his inability to walk for the last 8 months, from lack of daily regular exercise). So, the vet took him in, and about 20 minutes later, the vet comes to us and tells us that, in his own words, Your Dog is Dying. Then he went on to say that he checked his gums, and his gums were practically white. He said the gums should have a redness appearance, but they were white. He told us that Carlos has ANEMIA, and that Carlos was sitting practically still, almost lifeless, and was on oxygen. He tells us that his blood pressure was normal. So, I started to ask the vet about what it would take, and if it was worth it, to try to save Carlos. He said that first thing, Carlos would need a blood transfusion, to bring back some life into him. Second, in order to TRY figure out WHAT was causing the anemia, he would have to run further tests. He said that trying to pin-point the problem could, hypothetically, not be so easy to do, and may require an investigational journey that could ultimately lead us to possibly require us to take Carlos to specialists, etc, to try to figure out what exactly was going on. And then I brought up to the vet about Carlos's bruise on his butt, which the Vet said was the LEAST of Carlos' problems, and probably unrelated to his anemia problem, and a problem in which he did not know the cause, or did not know how to fix. (Note that I thought that his bloody mass at his buttocks area was probably from a bruise, because when he would sit down outside, he basically often would sorta slam his butt on the concrete floor, due to hind leg weakness, and I thought that over time, because there was no muscle there, it created a bruise, and the bruise probably wasn't healing due to some other systemic issue. My mom also told me that she thinks that bloody mass at his butt seemed to have been infected). So, anyhow, we asked the vet about the option/notion of trying to save Carlos, and the Vet said that it would potentially be a very complicated journey. We asked him about the anemia, and he said without doing further tests, he didn't know what was causing it, but he mentioned the likely things that could be causing Carlo’s anemia: he mentioned to us the most common things that are probably causing Carlo's anemia: 1. kidney failure, 2. an autoimmune disease (in which immune system is attacking red blood cells), 3. cancer and 4. bone marrow no longer producing red blood cells on their own. Those were the major things HE mentioned. Then, when my thoughts were a little bit more clear, I went outside of the vet’s office, and I started researching online of the causes of anemia. Besides the ones the vet mentioned, I also saw things like: toxins, an infection, and some other listed items, such as digestive bleeding, etc. Even though my thoughts were cloudy in that moment, what I did see there, as a list of what could be causing the anemia, well, they were all rather Serious things: if it was cancer, that's serious. If it was autoimmune disease, that's serious. If it was kidney failure, that's serious. So, whatever it was, they ALL seemed to me, at least at the time, all serious. (and remember, Carlos was 16, so, it probably WAS something major and systemic due to old age). So, I discussed it with my family, and we all collectively decided, with the information that we had at the time, that the best choice was to put down Carlos, because overall, he seemed like he was in bad health, and there seems to have been some systemic issue with his overall health. I mean, think about it....his skin got so thin at the butt area, and blood would leak/seep through his skin! He had his irregular heart beat, and he had anemia, and was low on oxygen as a result. So, we thought that trying to put Carlos on a journey of trying to save him, would have been emotionally draining to us, but also potentially unfair for the dog because we didn't know how complex the journey would have been for Carlos. So, that's why, at the heat of the moment, we decided to put down Carlos. It was not an easy decision. But, now, about 3 days later, and now that my thoughts are a little bit more clear, I regret one thing, and that thing is: should we have at LEAST ran some blood tests to get more information as to WHY Carlos was having the anemia. Maybe that information would have at least TOLD us WHY he had anemia, and thus reveal what exactly was going on in his body. THAT is what I regret...not going farther with the test. But again, we were in a moment of frantic emotions, and our dog was probably in an uncomfortable spot, with oxygen being fed to him, and so we made the decision to put him down on a moment of emotion and fear for the dog's well being. But again, I'm sitting here, and wondering if we ultimately did the right thing. And again, now that my thoughts are a little bit more clear, I'm regretting not going farther with a few more blood tests to REVEAL what exactly was causing his Anemia, which those blood tests could have at least shed some light on what is going wrongin his body - was exactly was causing his anemia. So, I'm trying to get some closure here, and I want to make sure that I made the right choice for the dog. Again, I feel bad for not at least having the Vet run some more tests to figure out the CAUSE of his anemia, which could have at least Revealed to us some more Information as to WHAT was going wrong in Carlo's body, which COULD have granted us the information to make a more careful decision if we should have ultimately put him down, or, you know, embark upon a journey to try to revive him, and treat the underlying condition (for example, cancer could have been TREATED with chemo, KIDNEY failure could have been treated with Shots, bone marrow issue could have been treated with bone marrow transplanet, etc). So, my question to you is: considering these facts, did we ultimately make the right decision by putting him down? Again, had my thoughts been a bit clearer, I think I would have at LEAST decided to run the blood tests to at least figure out WHAT exactly was causing his Anemia. But that thought didn't really clearly pop into my head until 3 days after the fact. And, you know, Carlos' overall health and quality of life wasn't great, AND, right before we brough Carlos into the vet, a good amount of blood leaked out of that blood mass near his butt, which we interpreted as a sign that his time was basically up. Anyhow, since I loved that dog so very much, I want to move on knowing that I made the BEST choice for Carlos considering all the facts and circumstances that the time. I wonder if I should feel regret for not thinking of asking the vet to take this with baby-steps to at least try to figure out WHAT was causing his anemia. (But again, whatever was causing the anemia, all the possible things that could be causing it seemed like they were ALL serious: again, things like cancer, kidney failure, etc). And then, we would have to have gone on a journey to pin point the problem, and then treat it as best as we can. But, at the time we also figured, at best, ***** ***** we WERE to save him, we have to figure he was 16 years old, and his hind legs were already non-functional, and if we did successfully bring him back to health, he still had this bloody mass at his butt, which the doctor wasn't sure what it was, and we figure the MOST he could live more would be maybe 4 months, or so, considering he was already 16. So, again, in short, I wish I could go back and at least run the test work to figure out WHAT caused him anemia. Maybe the cause of the anemia wasn't so bad...like maybe it was kidney issues that could have been fixed with some shots. But again, would this have been fair to Carlos? Would it be fair to try to save a 16 year old dog who was in that spot? Best case senario, we have to remember he was still very old. So, since the decision we ultimately ended up making was putting him down, do you ultimately think it was the BEST choice for him (even if his anemia was caused by something not all that serious)? Note: Carlos always weighed about 40 pounds. But he weighed only 28 pounds at the vet that day on November 5, 2021, the day he passed away (ie the day he was put down). And you know, considering his skin was so thin, that blood would seep through it, THAT to us indicated that he was really ready to go. And in retrospect, I think that even if the anemia issue was an easy fix, he still had this very thin skin at the bottom of his butt aread, where blood would leak through, suggesting that something else was going on. You know, was that thing a bruise? Why was his skin so thin? There were questions that swirled in our minds. Here’s the thing: I just don't want to live with the grief of the regret that I could have SAVED Carlos if I was only a bit more diligent in getting him tested, and approached it with a bit more clarity in my thoughts. I don't want to live with the regret that I put down a dog that potentially had another full year of life ahead of him. In other words, do you think we made the most optimal choice for Carlos, even though we made it with the most minimum information available to us.