i really find this mod useful when i pair it with ScanningRadar mod that can make you have dozens of kilometers radius of map revealed over time, but sometimes i do not want to delete the chunks but i want to delete just the fish since they can get to numbers like 80k or 80000 in active entities and using the command:

/c for _, v in pairs(game.player.surface.find_entities_filtered{type="fish"}) do
v.destroy()
end

makes my UPS come back but disables achievements and deletes ALL fish... (sorry if the above command is not written properly, i don't know how to use or disable this site's formatting.)

this mod here with a modification of this command could count fishes in the chunks have a chunk radius of fish to ignore, then a falloff of chunks where you delete more and more fishes! so radius 100 chunks, falloff 20 so 1 chunk deletes 1 or 2 fish, 10 50% fish so about 8 to 10 fish and 20 and on all the fish! (or randomly keep 1?)

basically this mod has everything needed, just that all you do is scan for fish instead of pave and player entities and you delete a number of them instead of the chunk! (fishes are an unforeseen problem that normally is not there since exploring the sea that far should not be easy but... using the command i go from 60k active entities to 1.5k so... UPS from 35 to 60.)

It would be possible and I could consider forking to just do fish removal.

In the mean time, I use this mod for the occasional one shot lua command: https://mods.factorio.com/mod/some-luaconsole
Then you can run commands without losing achievements.

well that would be nice, on one part i don't mind the achievements as much as the fact that the command removes ALL the fish... since i am playing with a few mods that do use them... (not like 80k fish of course and mining all the fish by hand would take ages!) this mod has the ability to count them and remove a more controlled amount.

simply put, the mod can work 100% the same up to the "delete chunks" phase and instead do a count fish phase then delete more per chunks on a radius based math.

i just noticed you also did the Scanning Radar mod so the same math for the near and far/radius math can be used to mark the beginning and end of that circle stripe, then that becomes a simple number to plug on the number of fish to delete portion. (beginning = 1 fish, end and beyond = all fish.)