Ive done a wee bit of research on the net, and found that the probable cause of many mimics quick death - is the technique to capture them. Cyanide is used to flush the octopus from its' den, and apparently the health affects only become apparent further down the line.
Perhaps the shock of moving to a new tank coupled with the cyanide poisoning is why many die within days.
The mimic tank doesn't require any rocks (well for filtration it does obviously), and an 8-10 inch deep sand bed is the "reccommended" minimum.
Temperature should be constant and water quality should remain high.
Dont change salt brands as some brands may kill them.
Subdued lighting is reccommended.
Apparently they like to swim around alot and may get frustrated and ink if they crash into the glass too much.
Colour changing is only to completly black, and this is only while angry or frustrated.
They may (but are unlikely to) have toxic venom, no-one really knows as a bite hasnt been properly documented - from what I could find.
The reason they are unlikely to be poisonous is assumed from comparison of other mimicing organisms, but is still just an educated geuss.
Thats the info I could find on short notice
, some animals have been given to the NRCC, and still died within days.
Oh, and lastly no mimicry has been reported outside of their natural environments - and apparently they make dull pets.
O'O, I know I told you this in my pm, just thought everyone might be interested.