I'll try to make this short/ish. My parents are divorced, and my mom has been really supportive of my new hobby. My dad, not so much. I used to have 4 tanks at his house. (55 Gallon reef in progress, 2 10 gallon freshwater juvenile predator tank, and a 5 gallon saltwater qt) I recently had one of my predators jump ship and died on the floor, so I took down the tank and it is now my reef sump. My snails and hermit crabs in the qt were in there for 6 weeks, and are now in the reef in progress, so I took that down as well. So, I only have the two tanks, a 10 gallon freshwater and a 55 gallon reef. I found a 40 gallon for sale on Craigslist, and I asked him about it, and he said no and walked away. I told him I was going to need a bigger tank eventually when I got the spotted climbing perch ( the predator in the 10 gallon) but he didn't let me. I want to ask again, but I want to ask as politely and as convincingly as possible, what should I try? I won't go against his rules, but I feel bad for having a spotted climbing perch in that small of a tank as he grows. Thanks all!