I target feed with meaty tabs (like algae wafers, but with meats) and with frozen formula one.
Horseshoe crabs need vast areas of open sand. They are not built to go on rocks, and are poor swimmers in open water. They need a very vigorous sand bed to support them--definitely would not add a sand sifting star with a crab--and tend to get flipped upside down easily--falling off a rock, or by a strong current of water. Sorry--but IMO, very few tanks can support them for long. Some species also get large--12-15 inches as adults, so even if you can keep it alive, it's going to need a big tank eventually. If I were to try keeping them again--yes, I bought one as well, and it died--I would have it in a tank with just sand--no rock of any kind, and slow water movement. Not really the typical reef setup, not even a good FO setup.
Horseshoe crabs need vast areas of open sand. They are not built to go on rocks, and are poor swimmers in open water. They need a very vigorous sand bed to support them--definitely would not add a sand sifting star with a crab--and tend to get flipped upside down easily--falling off a rock, or by a strong current of water. Sorry--but IMO, very few tanks can support them for long. Some species also get large--12-15 inches as adults, so even if you can keep it alive, it's going to need a big tank eventually. If I were to try keeping them again--yes, I bought one as well, and it died--I would have it in a tank with just sand--no rock of any kind, and slow water movement. Not really the typical reef setup, not even a good FO setup.