Nope, as Leslie has already explained, a beautiful mandarins dragonet would be doomed in a small aquarium suitable for Pixies. Live brine shrimp is by no means an adequate diet for them and they need a very large aquarium in order to forage for copepods and thrive.
Although their small size does indeed limit the suitable tankmates that can be kept with dwarf seahorses, I have found small pipefish do well with H. zosterae. I have a pair of small Gulf Pipefish (Syngnathus sp.) from Florida in my dwarf tank, which add a lot of interest to the aquarium because their behavior is so different from the dwarves (Giwojna, 2005). For example, when they’re just trying to blend into their surroundings, the pipes orient themselves vertically, heads up and tails down, and sidle up alongside a fake gorgonian or a tall clump of sea cactus, imitating one of the branches. It’s not a bad bit of camouflage, and once in a while one of the seahorses perches on a pipefish by mistake and gets taken for a wild ride, like a bareback bronco rider at a rodeo.
But when they’re hunting, the pipes slip into the beds of Caulerpa horizontally, and launch themselves like torpedoes at passing prey (Giwojna, 2005). Unlike the seahorses, which prefer to wait for their prey to come to them, the pipes dart out from hiding and snatch up brine shrimp right and left. It’s amazing how much faster and more agile they are than the pigmy ponies. At feeding time, the pipes go blasting around the tank like little guided missiles. Fortunately, with just two pipefish in the tank, they can’t make a serious dent in the swarms of Artemia.
Like the seahorses, these pipefish are livebearers and give birth to independent babies that are miniature replicas of themselves, except that the newborn pipes are totally transparent (Giwojna, 2005). They look like glass splinters or tiny transparent threads. Although I never made a serious attempt to raise them, a number of them survived for several weeks when left to their own resources in the dwarf tank. They were very good at concealing themselves amid the macroalgae, and especially liked to take refuge amongst the "bristles" of my Merman’s Shaving Brushes. The dwarf seahorses have no interest in them whatsoever, but I strongly suspect the parent pipes are cannibals. All in all, Gulf pipefish are inexpensive and entertaining additions to my dwarf seahorse setup.
For a nice splash of added color and natural beauty, I also like to add an assortment of Feather Dusters (Sabellastatre magnifica and Sabella sp.) amidst my beds of macroalgae. They are the brightly colored flowers blooming among all the greenery of this underwater garden. Feather Dusters are exotic, very showy, entirely harmless, relatively inexpensive, and completely compatible with dwarf seahorses (Giwojna, 2005). They are filter feeders and seem to eat the same newly hatched brine shrimp as dwarf seahorses, but they do best when fed phytoplankton (or commercial food preparations designed for filter-feeding invertebrates) with a baster from time to time.
The Lettuce Nudibranch (Elysia crispata, formerly known as Tridachia crispata, and still usually sold under that name) is another showy, totally innocuous invertebrate that’s a perfect choice for a dwarf seahorse companion. It is green with lavender spots and is covered with extravagant frills and ruffles that look like flower petals on an exotic orchid, but in fact they are the ruffled flaps of tissue (parapodia) that outline each side of the back of this two inch sea slug that lives in the waters of the Caribbean and Florida Keys (Giwojna, 2005). It’s an algae eater that dineson macroalgae such as Caulerpa sertularioides and is one of the few nudibranchs that do well in the aquarium, particularly a dwarf tank with a lush bed of Caulerpa (Giwojna, 2005).
I also have a handful of Volcano shrimp or Hawaiian red feeder shrimp (Halocaridina rubra) in the tank, not as food for the dwarf seahorses but rather as their tankmates. These colorful little saltwater shrimp resemble miniature peppermint shrimp, and usually do well with dwarves because of their size. They are too big to be eaten by the seahorses and too small to be any threat to them, and as an added bonus, they will produce larval shrimp that are perfect treats for the ponies. They are omnivores that do a fair job of scavenging and complement the regular clean-up crew nicely (Giwojna, 2005).
Along with the Volcano shrimp, Nassarius snails and Scarlet Reef hermit crabs (Paguristes cadenati) can serve as the cornerstones of the clean-up crew for dwarf seahorse tanks. The Scarlet Reef micro-hermits are colorful and interesting in their own right, and these harmless herbivores are the only hermit crabs I trust with my dwarf seahorses. A few of the colorful Scarlet Reef crabs make nice additions for a dwarf seahorse tank, as do the Nassarius snails, which are very active, efficient scavengers that handle the meatier leftovers.
Also worth considering are the tiny brittle starfish commonly known as Micro-Stars and often marketed as aquarium scavengers or sanitation engineers under that name. They start small and stay small, with a leg span that never exceeds the diameter of a 25-cent piece even when they are fully grown (most of these miniature brittle stars cannot span a 5-cent piece). Their legs are often attractively banded and they are very active and agile scavengers, moving more like miniature octopus that slowpoke sea stars. The micro-stars are fascinating in their own right, but it’s best to limit yourself to one or two of them, since they reproduce very quickly when conditions are to their liking.
As Leslie noted, captive-bred-and-raised pipefish are not available at this time. However, Florida Pets (http://www.floridapets.com/) is a good source for dwarf Gulf pipefish and the micro-stars. I have found their wild dwarf pipefish to be quite hardy in the aquarium.
There are also a couple of colorful little reef fishes you could try with Pixies, Carrie, such as Neon Gobies (Gobiosoma oceanops) or Flame cardinals (Apogon pseudomaculatus), but proceed with caution simply because they are not as hardy as Pixies and will compete with them for food. If you want to try them, it best to go with a single Neon Goby or no more than two Flame Cardinals to prevent them fighting among themselves. Be sure to quarantine any small gobies are Cardinalfish you consider keeping with your Pixies before you introduce them to the seahorse tank.
One thing that helps a lot is to aquascape your Pixie tank with an attractive arrangement of decorative macroalgae. Some of my favorites for this are Merman’s Shaving Brushes (Penicillus capitatus), Halimeda sea cactus, Udotea palmate fans, and especially Hawaiian Ogo (Gracilaria sp.) since its red-brown coloration contrasts beautifully with the predominately green plants. A tank heavily planted with macros such as these is a lovely sight and mimics the Pixies natural seagrass habitat well.
Best of luck finding some suitable tankmates for your Pixie tank, Carrie!