You can use silk plants from walmart or the dollar store to decorate your tank! Make sure they don't have metal wires though!! And you can use rocks from outside if they pass the vinegar test. Put a drop of vinegar on the rock, and if it fizzes, DON'T put it in the tank! And hot glue is safe to use if the sticks are clear, you can cut up the silk plants and glut it to a rock to make your own decoration!