Moved my year old betta into a 5 gallon tank. In addition to his little silk tree, I added a castle with fake plants and he loves to go through it and lay over it. HOWEVER, I NOTICED HIS BACK FIN IS TORN A LITTLE, and actually is getting white (he's been recovering from a long drawn out battle w.fungus). The decorative castle has some fake plants that look like he may be shredding his fin on them. Do you use regular tank decorations, or do you have to use specific Betta decorations? Thanks!