Welcome to AA!!! Im assuming your doing SW
. Like everyone so far has said, things can go very wrong in small tank very fast. Just not enough water for any leeway in water quality. I set up my first SW
tank few months ago and I have a 55 g and I wish I had done a bigger one. There are so many beautiful SW
fish, and you're only gonna be able to have 2-3 fish in a 10g- That's it. Look up fish on liveaquaria.com and decide which fish you love and what size tank they need, then decide what size tank to go with. Believe me, you're going to see so many beautiful fish that you won't be able to just want 2 or 3. If you get her involved with looking at fish, she'll find several she loves, trust me. Then you'll get your bigger tank!!