You can try to tie down some moss on top of it.Wouldnt recommend that you put it inside because of the limited light,no one likes brown dead moss in their tanks…Or you can put it vertically put the moss at the bottom and it will grow out of the windwos by itself eventually.
Another thing you can try is you can use it as a feeding dish since you dont want food to get mixed with the substrate you can try putting some food to make them get in maybe they get used to it.
As others have said, I would get some good sinking food and feed them in it. Once they get used to knowing food is there they’ll spend more time there. ✌️
Weeping moss can be held on with some cotton thread, and eventually attach and “fall” around the shipwreck on its own. Here it is in my tank! This moss is also only a month old so it establishes very fast with good light
EKCraft 
A dry dock. Some windlasses, pulleys, ropes and stuff. Carpenters tools. Pitch and some timber. Probably other stuff but I’m not a shipwright so idk.
Java moss coming out the windows. Any sort of moss is their jam and bread and butter
Idk but I’m just here to say this looks so cute and “shrimp wreck” is adorable. I think it will be perfect as the plants grow in.
Eta: omg I read it as shrimp wreck but you said ship wreck 😄 my little mountain of hardscape is called “Mt Shrimpmore”
Java moss is always a shrimp favorite and easy care plant
You can try to tie down some moss on top of it.Wouldnt recommend that you put it inside because of the limited light,no one likes brown dead moss in their tanks…Or you can put it vertically put the moss at the bottom and it will grow out of the windwos by itself eventually.
Another thing you can try is you can use it as a feeding dish since you dont want food to get mixed with the substrate you can try putting some food to make them get in maybe they get used to it.
As others have said, I would get some good sinking food and feed them in it. Once they get used to knowing food is there they’ll spend more time there. ✌️
Weeping moss can be held on with some cotton thread, and eventually attach and “fall” around the shipwreck on its own. Here it is in my tank! This moss is also only a month old so it establishes very fast with good light
https://preview.redd.it/w1f9wv0kwhtc1.jpeg?width=3024&format=pjpg&auto=webp&s=72223b520f7ccf3f9341e7b2f73fa18c35d71929