I've been following as I have plans to get a Toby puffer and a snowflake eel. This enthusiasm is getting me even more excited about getting one.
For a cover, egg crate seems good, but does anyone think it would be possible to do pieces of acrylic with small holes as a cover? I'm thinking like pencil diameter holes all over the place. Seems like it would be impossible for an eel to get through, but still allow decent air exchange and circulation.