Using pond dyes on a pond has the well known and documented effect of limiting sunlight penetration into the depths of a pond. However, what affect does this dye have on the nature of a fish responding to bait on a fishing line?
In short, the long lasting effects of pond dyes do not seem to have a tremendous effect on fish response to bait. In the short run, immediately after application, the “cloud” of dye may certainly reduce visibility of the fish in the pond. After the dye completely disperses (usually around 4-6 hours), then the dye adjusts to what conditions the fish was previously accustomed to.
On the other hand, if the dye is used for the first time, then an adjustment period would be needed for the fish to adjust to the change in the depth of color in the pond.
There are some concerns that dyes could affect the coloring of the fish, and this could be true due to the light penetration limitation that pond dyes produce. This would have no effect on the health of the fish nor on the people who would consume them.