40
40 is incorrect. I am on level 41 now and it still hasn't ended.
It goes in to your tank then in 4 hours you can sell them
they never die unless you dont feed them
here are some games i know on facebook: farmville, fishworld, roller coaster kingdom, petville, farmtown, happy island, and mousehunt
100
53+
A lot
As high as you can practically go
30 level then you just play.
The names of the creators are: Lance Priebe (Rsnail) Lane Merrifield (Billybob)
happy aquarium, fishworld, fishlife, fishisle, fishtycoon, and MAAAANNNNNY more
I think there are 3. But you have to complete all the levels (including Facebook levels) to get one of them. Then there is like a mega golden egg level.
There are currently 105 achievement levels, however you can continue to harvest treats and increase your experience level (XP) apparently unlimited. I'm currently at 248.