My Kelpie X used to catch jellyfish in the river and would hunt for fish, crabs, octopus and other things at the beach. She would walk around in the shallows and feel for things with her front feet. Then stick her head underwater and grab whatever she felt. She used to get all the brown jellyfish out of the river and put them on the bank.
At home when I was catching fish to sell to pet shops, she would sometimes steal them out of the buckets and eat them. I found this out when I took some fish to a shop and they said "What gives, we wanted 10 and you only gave us 9?" I apologised and said "I'm sure there was 10, but I will bring you a couple more tomorrow".
The following day I caught a couple more fish out and put them in a bucket. I turned back to the tank and in the corner of my eye I saw my dog come into the room. I watched her walk over to the bucket, stick her head in and pull a fish out. She then wandered off and ate it.