Put the screen saver on and walk away. If you have the four pets thing where you can put 4
in your tank put prego, zorf, stinky, seymore in your tank (prego if you have piranna
things, zorf to feed the guppies, stinky to catch you shells, and seymore to slow the
shells down) thats what i do and I have 20,000 shells by morning! easy shells here u
come!! Hope I helped!

my 7 virtual tank pets

stinky, prego, zorf, seymour, meryl, clyde and walter(punching my guppies or my 8
ultravores drops 2o shells..

haha!

buy the 7 limit egg for 45,ooo shells after you bought the 4 pet limit
(available only at the virtual tank)

try the challenge mode!
I tried it and I totally can't beat tank 4!