I've no knowledge of fish, but I'm curious about these ones that were so evident in large numbers in Wastwater on a very hot and sunny day.
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Look at the white tubercules on some of the fishes heads and the bright colours starting to appear on their flanks. This indicates to me that they are male Minnows coming in to their spawning colours which juvenile Dace would not be doing.
Lat/Lng: 54.4363, -3.3105
OS grid ref: NY150053