Insolent cat is insolent

Kaida loves napping on Ixchel's aquarium lid. I guess because it's warm and springy like a firm mattress. She knows it's not allowed - I have emptied many a squirt bottle for this behavior. She's already broken one lid. I thought the problem was solved by placing the aquarium high up on a shelf with little room for cats to crawl on top. I was wrong. She will always find a way.