Lately Henry has taken to bothering my other cats. He and Meeko have always enjoyed play fighting, but lately this is becoming more and more frequent, and rougher and rougher. Also, Henry is always bothering Phineas, trying to play fight with him as well, tackling him, etc., and I think this is starting to stress Phineas out. Also, I think he is very bored (and actually, I think this is why he is always bothering Meeko and Phineas, as he is not actually *aggressive* with other cats and will also snuggle with them after play fighting - I think it's a case of him just having too much energy and no other way to burn it) - he is always running from end to end of the apartment, and wandering around meowing, and I feel very bad for him. I am embarrassed to even post this, as I am afraid this is my fault - I live in a 500 sq foot, junior one bedroom apartment, and when I had three cats, there were never any problems, and providing necessary care (vet care, food) is not a problem, so against better judgment, maybe, I adopt a fourth cat (Henry) thinking there would still be no problems - so I feel very guilty now that he is bored and that he deals with it by bothering the other cats, as I think this may be a result of him feeling to cramped here - I have certainly learned my lesson about how many cats can be comfortable in a small space for future reference, however, since he is here already, I really, really want to avoid rehoming him, however, (I do not want to be selfish and keep him if he is miserable, but at the same time, I want to try everything first, as I don't think his chances of finding a new home are good, considering he has some biting/aggression issues [he came into my home with these, so these, at least, I do not think are a result of living here], and he has already been rehomed once in his short life), so I am looking for some solutions to his boredom problems -I have already ordered a second, large cat tree, as I think that giving him some vertical space to climb and explore may help. We already have a lengthy play session every day, as well. I am considering harness training him, as I think an hour or two outdoors each day might really curb his boredom, however, he unfortunately does not seem to enjoy the outdoors at this point - he has only been outside on the harness once, so obviously he was afraid, so in particular I am looking for tips on how to get him used to going outside on his harness, but I would also greatly appreciate any other suggestions on how to help him with his boredom (again, other than rehoming him, which I would like to only be a very last resort, after trying everything else to keep him happy here). Any suggestions, anyone?