They usually spawn in the ponds with the houses in the middle. I caught mine using around 100 energy and use the Minnow Death Fish spell, it's very helpful.
I have been trying to catch this fish every day since the update came out. I use winnow, charm, and I restock the pond every day. I have caught nearly 300 death school of fish and have not had a single fish get away, but I cannot have this fish show up. I am getting very upset at this. Is this fish anywhere other than the forum?