As far as uneaten food goes, some folks train their horses to a feeding station. I couldn't find the pic, but recently I saw a photo online from someone who built a feeding station - a small wide plastic dish suctioned to the glass, then a clear acrylic tube, like the ones used for undergravel filter powerheads, running from the top of the water down into the cup. He placed a small strip of eggcrate on the side of the cup, where the seahorses hitch to feed. To feed, he dumps defrosted mysis into the top of the tube and it slowly sinks down the tube into the cup. With the pumps off, the food mostly stays there - the seahorses eat out of the dish and then he sucks up the uneaten food using a turkey baster. It's really a great idea. Some people use big oyster shells as feeding stations instead of plastic cups so that it isn't such an eye sore.
Something to think about. I'm starting a big seahorse tank next week (converting my 110g tall tank) and I'm going to try to set-up this type of feeding station. I'll try to send or post pics when it's done.
- Skins