Our five year old Grandson has cancer and lives with us. He just had his 2nd chemotherapy out of 43. My wife asked the doctors about the fish tanks we have five of them(3 planted). They said fine but he is not to play with them or feed the fish. I am worried down the road they could make him sick when his immune system is compromised and is neutropenic. I also fear when I would have to break down the canister filters. those things get pretty gross. Does anyone here have any experience with this situation? Thanks in advance.