"copy and past" problem!

I am creating an animation where I have three identical objects (fishes) moving around.
they all share the same skeleton which is quite complex, and comprises a spine (with IK), bones in the fins and tails.
They are not parented, and move in an uncoordinated way.
now I want to create a sequence of actions (feeding behaviour) and hopefully without creating the keyframes for each bone in all fishes…as they are all different.
I don’t want them to do the sequence at the same time (hence cannot use a copy transforms constraint). And I cannot append the information, as it is for only one bone that I want to sequence to be copied…
How do I “copy and paste” the keyframes/informations from similar bones in identical but dissociated object?
many thanks for enlightening me!

If all the bones in each fish share the same names as the other fish then it’s simple. Select the armature with the action and open up the dope sheet to an action editor. Select the action you wish to copy to another armature and press the ‘+’ sign by the name of the action. This will create a new action that is the duplicate of the original with a suffix like ‘.001’ attached to it. What action is displayed in the action editor when an armature is selected, is the current action assigned to it. You can assign different actions to armatures by left clicking on the name field and you will be given a list of all actions, selecting a different action will assign it to the armature.

If it was me, I would while I had the first armature selected, select the original action. Then I would select the 2nd fish’s armature, and in the action editor, select the newly created action with the ‘.001’ suffix. Now the new action should be assigned to the other armature and you can slide the keyframes around to adjust the timing so it’s not the same as the first action.

One very important thing to note here is the idea of a ‘fake user’. If you create several actions and they are not assigned to armatures (or any object for that matter, be it a camera, light, mesh object, etc) then they have no users of that data and will be deleted when the file is saved. To avoid this, click on the ‘F’ button by the name, that will assign a fake user to the action and stop if from being deleted when the file is saved. When you click on an action name, it will open a list of all actions, actions with an ‘F’ to the left of the name have fake users assigned to them. Actions with a ‘0’ to the left of the name will have no users and will be deleted upon saving the file.