If it's soft it should still stick buddy. Get you a bowl, fill it with JUST water. Get your tank surface really clean, then wipe it with some water and literally maybe a drop of dish soap just to get it all slippery and happy. Put your decal in the bowl and let it soak for a few minutes till shes almost falling off the paper, then slide it off the paper onto your tank. The soap will basically let you slide the decal around to find the perfect spot. After shes on and all the air bubbles are out (if any) get a damp rag and dab it a little bit just to press it down a little more, hope this helps!