Copy and past keyframes? Duplicating animation parts?

Hello everyone,
I was wondering if there is some way to copy and paste a keyframe and by this i mean every value associated with the keyframe, not just copying one value at a time.

What i am trying to do is create a 1 minute long fight between prehistoric undersea monsters and i would like to splice in, or just create one swim loop within the clip and then duplicate(or copy and paste) it as many times as necessary to speed up the process of filling the down time in the battle scene.

Also is there any way to insert parts of other clips for an object with the same bones, bone names, same everthing?

Splice it no, unless you combine those animations in external software or using script to play animation continously.