good idea to put in a divider.
here is a couple links to some tank mate guides
http://www.seahorse.org/library/articles/tankmates/tankmates.shtml
http://www.fusedjaw.com/aquariumcare/seahorse-tankmates-whats-safe-whats-not/
good luck with her and keep us posted
looks to be female . male has a pouch for the eggs
oh i have overlooked one important ? what temp is your tank seahorses are susceptible to pathogens at temps above 74