you will probaly be able to get more help by posting this in the nano section as there tanks are 30 gall or less so they will be able to help you out more and go thorugh what you need and can get and can get
my views on this is a 10gal it pretty small yes you can keep corals rock and c.u.c but if you want a small tank with fish i would go with a 15 ,20 gall setup
10g Should be ok for a neon goby, or a firefish. You can keep a clown fish in a ten gallon, though this forum is divided on whether you should or not. Is that 10 US or UK gallons?
I'd head over to the nano section for more help with this.