I just read that you should not have a tight-fitting lid that completely covers your tank because you won't get enough oxygen/gas exchange to the tank. Is this true? I thought I should cover it completely so fish can't jump out. I have a glass cover and then I cut the plastic strips to fit around the equipment. I don't have a sump and I don't have room for one. I have a strong powerhead and good skimmer. I've had the tank set up for a few months and the fish and inverts seem healthy so far. I don't have any jumpers yet but I might want to get a sixline wrasse in the future.