I have a question on adding decorations to my aquarium?

Good question! I would say to put a couple of cute toys that are lead-free and that do not contain any harmful chemicals (if it's possible to tell which ones are okay). I used to have goldfish, and I only put in colorful rocks in their bowl to be on the safe side. But I think it would be best to go to a pet store and or ask an animal care worker what is safe for your type of fish to put in their little "home." :) I hope this helped you and take care. I'm sure your little buddies will appreciate you making their tank decorative :D