4th Gen when try to find pokemon it shows red dot why is this?

[koskesh101]

that is not true because i caught a pokemon that a red flashing on map in the great marsh

soz i agree to its a bit like what im sayin

 

[Ayano Katagiri]

It means a cave.. Nothing else..

Blue - Outside
Red - Cave/Dungeon Etc.. [Inside]

Gible shows up as blue, therefore rendering your idea incorrect.

Likewise, National Dex Trophy Garden Pokemon appear Red.