A block that will take care of your squids for you :D Build a 5x5x4 structure, filled with water. It must be made out of a solid blocks (cobblestone, stone, hardened clay ingot blocks and such (if you ever used xycraft... you'll probably be able to use the same blocks that you used to build tanks)) and the walls can be made out of glass as well.
Here's an example:
The Ink Harvester block MUST go on the top or bottom in the exact centre!
Inside of it make sure you have AT LEAST 2 squids!!! After all that is done it might take a few seconds but when you see the squid eyes on the block spinning. That means it's working! (Right clicking it will force the activation if everything complies with what I said before).
It will look like this:
The GUI will look like this, This is where you will find the inksacks and feed the squids:
You can feed them any thing that is edible: