plecos paint stripping

So I just got done doing a water change on my mothers tank and I noticed that the paint was being stripped off the Easter Island head decor that's in the tank(her tank is spongebob themed). I didn't really notice it until now because the paint is resin is gray and the paint is blue-gray so there's only a slight difference in color. I guess I don't have much of a choice but to move them out of that tank right? I thought about just taking that piece of decor out but then I'd be worried about them going after the pineapple house.

My 30gal metaframe is the tank they were supposed to go in but I wanted them to grow a little in my moms tank first so that they had some size on them before they went in with bigger more feisty fish. Crazy fish. Hopefully the paint doesn't have any harmful effects on them.

My plecos have eaten the paint off of those fake decorations. I've even repainted some of them, only to have that eaten off as well. It doesn't seem to have hurt them.

Thanks Betty