Residents of Fishville

Stages Overview

Egg - couple second "ooh I bought a fish" stage

Baby - can't sell your fish (not that you'd want to waste your investment ), some fish you can tell how hungry they are simply by noting their belly "size"

Junior - from egg to this point is the time interval stated in the store, fish sells at price stated in store, and fish becomes larger. This stage has a couple levels (3) with each taking the same time as it took to get to Junior. Each level in the junior stage increases displayed size, coins earned on selling, experience (xp) earned upon selling, and how long a fish can go without food.

Adult - From last junior level to this stage is same interval as before. Additionally, growth interval changes to one day. This means fast growing fish can be left for several hours without dying.

When the adult point is reached, the growth meter will still continue to rise, but level 4 is currently the last increase in coins/xp received for selling.

Feeding
Fish need to be fed at least once every level. Time from full to starving is twice the growth rate. As the fish gets hungry, it will get a yellow food icon, red food icon, then the red food icon will blink, and finally the fish will die if not fed. Dead fish can be removed with +1 to your experience. At this time, dead fish cannot be revived.

Special Options
Hover and click a fish using the default/multi tool to get the options of naming and moving. If you name your fish to something other than it's species name, then little hearts will show around the fish's level name (Junior Fish or Adult Fish). You can also name fish at the same time you buy them.
The "Move" option lets you change which tank the fish lives in.

Premium Fish
Some fish may require using premium game funds, Sand Dollars, in order to purchase. Instead of showing a gold coin next to the fish price, you will see a green one. Sand Dollars can only be gained through levels, mystery boxes, and purchasing with real world money (Zynga has removed offers-for-cash due to previous issues). The sand dollar cost is per fish. So buying 2 fish of a 1SD fish type will cost 2SD.