How do I fish?
To fish and for when you want to place waters on your farm, you will need to make sure that you are showing waters in your preferences. There are both coin bought waters and FarmCash waters so 3 options need to have a check mark in them to be able to see all of the waters:

If you make changes to your preferences window please remember to click on the green check mark at the bottom of the window to save your changes.
You can catch fish using the fishing rod or with one of the
fishing boats when you own them from ponds, lakes, rivers or sea coasts on your farm and when hired to fish for other farmers.
The fishing rod can be found by clicking on the Yellow Tool box. Click on the tool to use it then click on a water to start catching fish. When you are done fishing, click the green man to stop using the tool.
To fish waters that could be placed off the edges of a farm, you will need to own at least the smallest sized Turbo Fishing Boat.

How do i know when waters are ready to be fished?
Move your mouse pointer over each water, the tooltip will display the name of the water, how many fish, how much bait you have for that type of water. If the waters have been recently fished, it will also display how long until they are ready again. If there is no time displayed, they are ready to fish.
In this example, the Big Lake with Boat is ready to fish, it has 199 fish, and there is 400 freshwater bait...
In this example, there are 0 fish, so the lake has already been fished, and will be ready again in 7.9 hours. It also shows there are no freshwater bait available for fishing.

How to get bait and what it is for is explained in a later post in this thread Using bait.
You do NOT have to have bait in order to fish your waters, you will still get fish without it.
Note: Waters that have just been bought or placed from Item storage will take some time before they are ready to be fished.
- Coin waters will be ready 20 hours after placing them.
- Farm Cash waters will be ready 8 hours after placing them.
For information on all the Fishing boats so you can fish much faster, please click on this link to go to the Fishing Boat post in Chapter 21 Tools:
What is the fishing boat?