How do I animated tiles

I get that we cant use tilemap in a sense of sprite frames but Id like to do something like this Tile index at 55 change to 6 and then again oto 8 and then back to 55 sort of like a sprite animation but with tiles and yes this will be a very large same tilemap just for the water i saw how one guy did it on the scratch program and i know they both use the same stuff.

Or is it impossible due to contruct 2 behavior, and if so then is anyone willing to make a plugin for these things. ?

ok so I learn that the data is stored in Json fine. I see this line of code {"c2tilemap":true,"width":71,"height":40,"data":"0,1,2,3,4,5,2834x-1"}

please correct me on this but 0,1,2,3,4,5 are the index and 2834x-1 Is the non used area. Is there a way to do something like this Every tick change all index =5 to let say to 6 and then to 7 and then back to 5 in a loop?

The reason why i want to use tilemap is because I want to quickly flesh out background without adding in sprites from hell.

It's possible, but depending on how many tiles are displayed at once you might hit a performance block. What you basically need to do is loop through all displayed tiles, if any tile with index x,y,z are found, normalize them to the one that should be displayed according to the current System.Time value.