The thing you want to remember about seahorses is that they are very slow and methodical eaters. I have heard someone kept a bangaii with their horses and hasn't had a problem. The clowns may out compete them. I'm sure others will give you more advice than I am able to as I just started keeping horses. If you go to seahorse.org and look in the tankmates section and maybe do a search on the kinds of fish you are looking to keep, I'm sure you will find post from people who have had experience with combining the 2. HTH