Halp! I got this succulent from my sister as birthday gift last September. It was tightly packed with a lot of other succulents and most of them didn't survive. I have been watering it as recommended. But this morning I saw one of the bigger leaves turn black at the base. I have since removed it. Don't even know what exactly is it. Some kind of Tiger Aloe!? The plant hasn't grown a lot over the past few months. Please advise


