one more question about eel tank

[salt life]

would it be safe to use egg crate for the lid of the tank? Both eel I have in the tank don't try to escape and aren't to crazy when they swim around. The glass lids block alot of light and open top is better for oxygen exchange?

 

[nofishnplease]

i use egg crate...never had a problem...i have an SFE about 18inches

 

[salt life]

do you hold it down with anything or your eel doesn't try and get out?
I don't want to buy it and then something does happen but i've had both for a while and they only get really active at feeding time.. do you agree about the aeration thing?.. and what benifits come with having an open top tank?
thank you for responding.