As far as saltwater aquarium supplies are concerned for seahorse aquariums, you are definitely going to need some living rocks, which help regulate bacteria levels in saltwater tanks and provide excellent "holdfasts" for seahorses.
Aquarium Live Sand 20 lbs Florida Aquatic substrate
 Aquarium Live Sand 20 lbs Florida Aquatic substrate
$5.99 (0 Bids)
Time Left: 3h 13m
5 Gallons High Purity Aquarium Magnesium Chloride Reef
 5 Gallons High Purity Aquarium Magnesium Chloride Reef
$69.99
Time Left: 9h 44m
Over 50 lbs of Assorted Live Rock and Shelf Rock
 Over 50 lbs of Assorted Live Rock and Shelf Rock
$39.99 (0 Bids)
Time Left: 10h 2m
Aquarium live rock marine
 Aquarium live rock marine
$0.99 (2 Bids)
Time Left: 19h 54m
Artificial Decoral Coral Aquarium 4 PICE LOT SALT WATER
 Artificial Decoral Coral Aquarium 4 PICE LOT SALT WATER
$0.01 (1 Bids)
Time Left: 1d 2h 18m