Hey everyone. I'm in a bit of a spot. I have two Blue Candle (Azureus) cacti, Harry and Lloyd. Harry is about 6 or 7 inches tall, and Lloyd was about 3. They shared a pot together until earlier today. Lately, Lloyd's been getting smaller and darker It's now much shorter, thinner, and the needles have gone from a pale yellow to a golden/brownish color. It is also kind of squishy (i noticed when I moved the cactus out of the pot). The color of its skin is still green, so I have hope. I took Lloyd out of the pot and planted it (temporarily) in half of a plastic cup that I filled with a little of the pot's soil. I have a feeling that some of you are cringing right now, but I'm a college student with limited resources, and I plan on taking more permanent steps once I have everything planned out. Anyways, I took it out because I was afraid that maybe Harry, who is at least 4 or 5 times larger than Lloyd, might be "hogging" the pot. I have absolutely no experience in cactus care, these are my first and I'm very attached to them (they were a gift from a very loved one). Any help that you guys would be able to provide would be appreciated.
Very difficult to say without a picture, but it sounds as if Lloyd is infected by one of these disorders which kills the plant from the inside. When you see the symptoms, it is usually too late. It was probably a good decision to remove it from the pot, otherwise Harry might have become affected as well.