Nudibranches & community fish

[my2rotties]

I just received a "tank warming gift", and cannot find any relevant info on my issue. It is a beautiful pink nudibranch, and it's floating in the bag about to go back to the LFS. What is their line of defence since they are so brightly coloured?

Is it poisonous due to the bright colouration? Will my puffer eat it, which is a no brainer since it looks like a fishing angler? How long can one be bagged since I was not planning on driving into the city.

Sigh...