2.8 Animation stops when copying keyframes in dopesheet

I have been searching and i’ve found posts that touch on this issue but one that quite covered a solution.

I’ve got this fish and it has been animated and I am trying to copy the keyframes so that i can continually loop the animation of the fish.

I have gone into the NLA and unpinned the actions in there (as recommended in another post I found) but even still, whenever I copy and paste the keyframes the animation doesn’t continue.

This image, you can see the un highlighted key frames, then in yellow is all of the keyframes I have copy and pasted – but as I play through, the animation only happens in the beginning (unhighlighted keyframes).

Any and all help would be greatly appreciated.

Thanks in advance.

I’m in Blender 2.8 on a standard 2016 Mac pro 15 inch.