Yes, sir — the "Comments" section on the online order form is for any special instructions you may have regarding your order. That is where you can request the particular traits you want in your seahorses. That’s the place where you can specify if you want seahorses of a certain gender or color, or perhaps a pregnant male… When Ocean Rider subsequently fills your order, they will look over the current crop of seahorses and do their very best to select specimens that meet your specifications from their available livestock.
You can always get either males or females, and if you’re willing to pay a little extra, you can obtain a pregnant male. You can also request a seahorse of a particular color. They will then try their hardest to pick out the seahorses that are the closest possible match for your preferences, although there may not always be specimens available of the particular color you are looking for when your orders to. It’s the next best thing to handpicking the seahorses yourself.
I should point out that you cannot keep Mustangs and Pixies together in the same aquarium. They have different requirements, particularly for feeding, which makes keeping the two species together impractical. You will need to either pick Mustangs or Pixies and set up an aquarium that’s tailored to meet their needs.
Best wishes with all of your fishes!