Hi there, I'm new to these forums and to keeping plants in general. I received a small cactus as a gift last summer (not even sure what kind it is, so that information would prove useful if someone could identify it for me) and while it's been perfectly fine for nearly a year and actually grew quite a bit, it's starting to shrivel up. I don't think it's never really rooted particularly well, it's felt pretty "loose" in the soil but I've never kept a cactus before so I wasn't sure if that was normal or not. I just noticed it this morning. Instead of being a "barrel"-shape, it's more of a cone-shape now. And I believe that it also feels "soft" instead of firm to touch which wasn't the case before. It sits on a window sill that gives it a few hours of sunlight each day and I think it's watered once every 10 days with tap water. Is that too much? What could be the issue here? Is it rot, poor rooting, poor nutrition? Any answers would be greatly appreciated.