new seahorse tank

Dear Sindy:

Estefano is correct — your 12-gallon nano cube is way too small for any of the greater seahorses such as Mustangs or Sunbursts (Hippocampus erectus). If your only option is a 12-gallon nano cube, then you’ll need to limit yourself to the miniature seahorses or perhaps the Shetland pony class of small seahorses, exemplified by Zulu-lulus (H. capensis)

For example, your nano tank could support a full colony of Pixies or dwarf seahorses (Hippocampus zosterae), or a group of other small seahorses such as the short-headed seahorse (Hippocampus breviceps) or the closely related H. tuberculatus. These are all miniature seahorses that reach an adult size of about 1.5 inches (in the case of H. zosterae) or about 3 inches in length when fully grown, in the case of H. breviceps or H. tuberculatus.

Allow me to explain a little more about these different miniature seahorses and their requirements so you can determine if any of them are suitable for your needs and interests.

Pixies or Dwarf Seahorses (Hippocampus zostrae)

The first species you might want to consider are Pixies, which are Ocean Rider’s strain of domesticated dwarf seahorses (H. zosterae). Dwarf seahorses are the smallest of all the cultured seahorses and a whole colony of them can live happily in a 15-gallon aquarium. They are the easiest of all the seahorses to breed and raise, and they are the least expensive ponies, which makes them affordable in groups.

However, three factors make Pixies or dwarf seahorses (H. zosterae) somewhat more demanding to keep than the larger breeds of seahorses such as Mustangs and Sunbursts (Hippocampus erectus):

(1) Their need for live foods.
(2) The small water volume of typical dwarf seahorse setups.
(3) Their susceptibility to aquarium hitchhikers and stinging animals (e.g., hydroids, Aiptasia).

Because of their small size and sedentary lifestyle, dwarf seahorses cannot be consistently trained to eat frozen foods without risking polluting the aquarium with uneaten food. As a result, the adults must be provided with copious amounts of newly-hatched brine shrimp (Artemia nauplii) at least twice a day and the fry must have access to bbs throughout the day.

This means maintaining a battery of brine shrimp hatcheries and hatching out large quantities of brine shrimp on a daily basis. If you are not proficient at hatching out brine shrimp or consider that to be too much of a hassle, then dwarf seahorses are not for you!

Because they are so terribly tiny — adult H. zosterae are only about the size of your thumbnail and half of that is tail — dwarf seahorses do best in small aquaria of 2 to 5 gallons to facilitate maintaining an adequate feeding density of bbs. Such a small volume of water is more susceptible to fluctuations in temperature, pH, and specific gravity than larger aquariums, and the water quality can also go downhill much faster in such small tanks than in large setups.

This means that dwarf seahorse keepers must practice diligent aquarium practices and an accelerated maintenance schedule in order to stay on top of water quality. As an example, water changes should be made weekly or biweekly, rather than monthly or bimonthly. This is not really onerous at all, since the water changes are so small (a fraction of a gallon to 1 or 2 gallons at most, depending on the size of the dwarf tank). It’s an easy matter to prepare and store a month’s worth of freshly mixed saltwater in advance, and I then find that I can perform a water change, vacuum of the bottom of my dwarf seahorse tank, and clean the sponge filters in no more than 5-10 minutes tops. But if the aquarist is not diligent about water changes and aquarium maintenance, dwarf seahorse setups can "crash" more easily than bigger, more stable aquariums with a larger volume of water.

The need for an accelerated maintenance schedule and daily feedings of live foods thus makes dwarf seahorses a bit more demanding to keep than the greater seahorses.

In addition, because of their diminutive dimensions, dwarf seahorses are susceptible to the stings from hydroids and Aiptasia rock anemones, which normally do not present a risk to the larger breeds of seahorses. Hydroids in particular are especially problematic for dwarves because once they find their way into a dwarf seahorse setup or nursery tank, the dreaded droids can explode to plague proportions very quickly because conditions are ideal for their growth: perfect temperatures, an abundance of planktonic prey that is renewed every few hours, and a complete absence of predators. As they proliferate and spread, they will soon begin to take a toll on the seahorse fry and even adult dwarfs can succumb to multiple stings or secondary infections that can set in at the site of a sting (Abbott, 2003).

The type of substrate — aragonite, black sand, crushed shell, coral sand, or a bare glass bottom — doesn’t seem to make much difference at all. It’s just that nursery tanks and dwarf seahorse tanks are perfect environments for culturing hydroids, and once they find their way into such a system they go forth and multiply with a vengeance. So unless dwarf seahorse keepers take special precautions, they can find themselves waging a losing battle with an infestation of hydroids, and that’s something that hobbyists who keep larger seahorses simply never need to be concerned about.

However, dwarf seahorses are widely considered by far the easiest seahorses of all to raise. They are prolific, breed readily in groups, and produce large, benthic fry that accept newly-hatched brine shrimp as their first food and reach maturity in as little as three months. They are the least expensive of all the seahorses to own and a dwarf seahorse aquarium can be set up far more economically than a system for keeping the larger seahorse species.

Dwarf seahorses are therefore ideal for breeders and anyone operating on a shoestring budget. Pint-sized and prolific, these pigmy ponies are the perfect pick for anyone primarily interested in rearing or for any seahorse keepers who can’t afford to devote too much money or space to their hobby. Hippocampus zosterae is the best choice for the novice who wants to learn more about keeping and breeding seahorses before moving on to the big boys. More budding seahorse keepers have cut their teeth on dwarves than all the other seahorses put together. H. zosterae is the right pick for newbies who would like to try their hand with seahorses for a modest investment, or for hobbyists with a tight budget, or aquarists looking for captive-bred seahorses that are a snap to breed and a breeze to raise, or anyone captivated by keeping tiny elfin creatures no bigger than your thumbnail.

All things considered, I feel that the many advantages of keeping dwarf seahorses far outweigh the drawbacks we have outlined above. But you would likely have to modify your 12-gallon nano tank considerably to prevent it from creating too much current for the dwarfs and to keep the filter from "eating" all of the newly hatched brine shrimp before the pigmy ponies had a chance to eat it.

And here is a species summary that describes Hippocampus breviceps and the closely related H. tuberculatus, the other miniature seahorses that would be suitable for a 12-gallon nano cube:

Hippocampus breviceps (Temperate, Benthic)
Common name: Short-head seahorse, Short-headed seahorse, Short-Snouted Seahorse.
Scientific name: Hippocampus breviceps Peters, 1869.
Synonyms: possibly Hippocampus tuberculatus.
Maximum size: up to 4 inches (10 cm) in height.
Climate: temperate; 21° S – 43° S.
Distribution:
Indo-Pacific: endemic to southwest Australia.
Meristic Counts:
Rings: 11 trunk rings + 40 tail rings (tail rings vary from 39-43).
Dorsal fin rays: 20-21 (varies from 19-23) spanning 3 trunk rings + 1 tail ring.
Pectoral fin rays: 14-15 soft rays (pectoral rays vary from 13-15).
Anal soft rays: 4 rays.
Adult height: 1-3/4” to a bit over 3” (4.5-8.0 cm).
Morphometrics:
Snout length: 3.0 (2.4-3.5). In other words, the snout length will fit into the length of the seahorse’s head an average of 3 times. That means H. breviceps has a relatively short, stubby snout that’s only about 1/3 the length of its head. It is the snub-nosed appearance of H. breviceps that gives it common names such as the Short-snouted Seahorse or Short-headed Seahorse.
Other distinctive characters:
Coronet: tall, columnar or knob-like.
Spines: irregularly developed, some very low, others have very prominent rounded tubercles on the tail or back (dorsal surface).
Key Features: many adults sport a mane of thick skin fronds on the head and neck region; mature males have a very prominent brood pouch.
Adult height: 1-3/4” to 3” (4.5-8 cm).
Color and Pattern:
The base coloration of H. breviceps ranges from yellowish to brown to purplish, often with a reddish tint. Many of these endearing pug-nosed ponies have many dark spots on their heads, as well as numerous pinpoint-sized white dots on their abdomens, and are further adorned with striped tails.
Breeding Habits:
Breeding Season: usually from October to January.
Gestation Period: 23-26 days.
Brood Size: average brood is about 35 fry.
Size at Birth: ~1/2” (14 -16 mm).
Onset of sexual maturity: 5-6 months.
Pelagic/Demersal (benthic): fry are primarily pelagic for the first 2-4 weeks although they will hitch occasionally.
Ease of Rearing:
Thanks to their high-capacity brood pouch, breviceps males give birth to an average of 35 amazingly large babies (1.4-1.6 cm). The newborns go through a pelagic phase but are able to eat baby brine shrimp from the first, making them intermediate in difficulty. Rearing H. breviceps fry is similar to raising H. erectus, but perhaps a little easier due to the smaller number of hungry mouths you must feed (a few dozen fry versus a few hundred newborns).
Natural Habitat: Inhabits weedy inshore waters and occupies much the same habitat as the Weedy Seadragon (Phyllopteryx taeniolatus).
Natural History:
Hippocampus breviceps is similar to the dwarf seahorse (H. zosterae) in the fact that it is a colonial seahorse that rarely occurs singly or in lone pairs. It is typically found in groups that range from small aggregations to large colonies living in various weedy habitats. It is often found among patches of Sargassum attached to rocks on a sandy bottom, and the specimens that live amidst the Sargassum typically have elaborate, well-developed cirri along their heads and backs. In deeper water, H. breviceps may be found on sponge reefs.
Rudie Kuiter reports they feed close to the sand or rubble by day, hunting mysids that congregate along the sandy substrate. By night, however, they seek shelter well above the substrate to avoid bottom-feeding predators such as crabs, and often assemble in small groups high in the weeds (Kuiter 2000).
The pelagic fry have proportionally much longer snouts that the snub-nosed adults (Kuiter 2000). Interestingly, Kuiter has noticed that the fry which remain pelagic the longest tend to develop longer snouts than the fry which settle out and assume a benthic existence at an early age (Kuiter 2000). He reports that during the summer months large numbers of H. breviceps fry can be observed clinging to rafts of floating vegetation carried on the strong outgoing tides that occur near the full moon (Kuiter 2000).
Perhaps because it is found in group situations in which partners are readily available, H. breviceps is known to be polygamous both in the wild and in the aquarium, showing no mate fidelity. Egg diameter is 1.6 mm.
Preferred Parameters:
The following readings are based on the rearing program for Hippocampus breviceps Tracey Warland conducted for several years at her seahorse farm in Port Lincoln, Australia:
Temperature = range 65°F to 75°F (18°C-24°C), optimum 66-70°F (19°C-21°C).
Specific Gravity = range 1.020 – 1.026, optimum 1.024
pH = 8.2
Ammonia = 0
Nitrite = 0
Nitrate = < 20 ppm
Suggested Stocking Density: 1 pair per 4 gallons (15 liters).
Aquarium Requirements:
H. breviceps is a smallish seahorse best suited for small aquaria of 10-30 gallons (38-114 liters). Aquaria of this size can be set up as either a basic tank with undergravels (or sponge filters) or as a standard SHOWLR tank, and be should heavily planted with Caulerpa or macroalgae to simulate the weedy habitat this species prefers. A protein skimmer and UV are always advisable, but may need to be confined to a sump on small tanks. These are temperate seahorses, and I recommend using a mini aquarium chiller to keep the water temperature in the upper 60s to perhaps 70°F (19°C-41°C) at all times.
They would thrive as a colony in a species-only tank, but also make excellent tankmates for other Australian seahorses with similar temperature requirements such as H. abdominalis and H. whitei.
Juvenile Rearing Tanks:
Newborn H. breviceps can take newly hatched brine shrimp (Artemia nauplii) as their first food (Tracy Warland, pers. comm.) and are suitable for the “easy” rearing method. The fry undergo a free-swimming stage for 2-4 weeks and will thus do best in kreisel-style nursery tanks designed for pelagic fry such as those described earlier for rearing H. ingens or H. reidi. In-tank nurseries with drum-type, goldfish-bowl inner chambers that produce a circular flow are another good alternative for rearing this species.
Diet, Nutrition, and Feeding Techniques:
Tracy Warland of South Australian Seahorse Marine Services suggests the following feeding regimen for H. breviceps and the other seahorses she raises (Warland, pers. comm.):
<open quote> “I recommend feeding a mixture of both frozen and live foods. Each food fed out contains different levels of nutrition and a mixture of these different food sources will enhance longevity and health.
Frozen mysids (Mysis relicta seem to be the best nutritionally packed mysids) can serve as the staple diet. If they cannot access M. relicta, most other frozen mysids are enriched and they would be fine.
Frozen enriched brine shrimp can also be used, especially for smaller horses as the size of the food is quite small and enables young seahorses to eat a food sized according to their snout. Young seahorses are trained to eat frozen foods with frozen enriched brine shrimp before being fed out the larger frozen mysids.
Live Brine Shrimp can also be used as a treat once weekly or fortnightly to enhance the variety of the diet. It can be enriched with various algae cultures or even algae pastes and powders to give a better nutritional profile. Some good examples are Spirulina (good for the immune system), any of the Tetraselmis sp., Dunaliella salina (contains beta-carotenes which enhance colours), or Isochrysis and Nannochloropsis (which contain good HUFA content).
If available there are also quite a few other good foods that can be added to the diet: live mysids, skeleton shrimp, amphipods, etc.
For babies a mixture of copepods, baby brine shrimp and even rotifers works well too. Enrichment of all foods offered to babies is highly recommended to improve growth rates and longevity in later life.
At the facility here we feed out a mixture of all of the above to ensure that the nutritional needs of the seahorse are being catered to; they are all trained to eat frozen foods before leaving the facility.” <end quote> (Tracy Warland, pers. comm.)
Discussion:

Hippocampus breviceps and H. tubercultatus are separate species.

Hippocampus breviceps is often confused with the Knobby seahorse (Hippocampus tuberculatus). The two species are very similar in outward appearance and behavior, but there a number of key differences between them. Most notably, they differ in their size, temperature requirements, and the nature and behavior of their fry.
For instance, although their newborns are similar in size, H. breviceps fry are pelagic while H. tuberculatus fry are benthic (demersal) from birth. Breeders thus have no difficulty telling the two species apart.
The temperature requirements of these two seahorses also differ. The Knobby Seahorse (H. tuberculatus) is a warm-water (subtropical) species that prefers water temperatures of 72°F to 75°F (22°C-24°C), whereas H. breviceps is a cold-water seahorse that requires temperate conditions (Warland 2003).
Finally, H. breviceps tends to be less knobby and is much larger than H. tuberculatus when fully grown (Kuiter 2000). The adult height of a large breviceps is about 10 cm or a bit under four inches, while H. tuberculatus may reach 5.5 cm (just over 2 inches when fully grown (Kuiter 2000).

Little Males with BIG Pouches

Breeding males have an enormous brood pouch, which is hugely expanded all out of proportion to their bodies when they are courting. Alisa Abbott has aptly described a courting male breviceps with a fully inflated brood pouch as resembling “a three-inch fuzzy pipe cleaner that swallowed a golf ball” (Abbott 2003).
Outside the breeding season, however, the male’s outsize pouch shrinks away to almost nothing, making it very difficult to even sex these seahorses at that time of year (Lawrence 1998). Not until the water temperature heats up again and breeding begins anew is do the pouches of the “emasculated” males regain their full glory and impressive dimensions (Lawrence 1998).
Together with H. tuberculatus, these are the smallest of all the Australian seahorses. Hippocampus breviceps are captivating little pug-nosed seahorses that barely reach 3 inches in length when fully grown. They are well known for the feathery fronds or cirri that often adorn their head and neck, an attractive feature that makes them popular with aquarists.
However, there are two special considerations H. breviceps keepers must keep in mind. First of all, they are temperate seahorses that do best at 66°F-70°F (19°C-41°C). Don’t let that deter you, however, if you fancy these little charmers. Miniature aquarium chillers are now available that would be more than adequate for the small tanks H. breviceps does best in. These mini units are surprisingly affordable and seem tailor-made for the Short-Headed Seahorse keeper.
Secondly, they are small seahorses (2-4 inches) when fully grown, and the six-month-old subadults that are shipped from the breeders in Australia are even tinier (1” to 1-1/2”). Many breeders prefer to ship their farm-raised seahorses at around the age of 6 months because the species they rear are sexually mature by then and ship extremely well at that age (Tracy Warland, pers. comm.). They also feel shipping the 6-month-old young adults gives the hobbyist a chance to grow along with their seahorses and enjoy them all the longer. All of which is perfectly true and works very well for the larger breeds, but can become a concern with small seahorses like H. breviceps and H. tuberculatus.
That concern is simply that the 6-month breviceps and tubers often aren’t ready to go into the main tank with fully-grown adults when they arrive. They may have trouble holding their own with the big boys at first and do better when kept in a small grow-out tank for several months of target feeding before you transfer them to your display tank (Abbott, 2003). They will do best in tanks of 10 gallons (30 liters) or less during this grow-out period and need small frozen foods initially, such as the smallest brands of frozen Mysis or even frozen brine shrimp.
Bonus Tip : a quarantine period is also recommended for newly arrived breviceps, especially for the American aquarist. This is simply because Australian seahorses cannot be shipped directly from the breeder to the hobbyist in the USA; instead, they are received by a distributor where they are held with other seahorses from around the world before being transshipped to the hobbyist from this outlet. In the US, the quality of the care the Australian imports receive at the holding facility will have a great effect on the health of the specimens that are delivered to the home aquarist, and the hobbyist must deal with the possibility that his seahorses where exposed to undesirable organisms during this mandatory stopover. Savvy seahorse keepers will use this to their advantage, simply using their stay in quarantine to give the new arrivals a chance for further growth and development in a protected environment where they can receive the aquarist’s full attention and care. Far from being a drawback, the quarantine period should be regarded as a golden opportunity to get the new ponies off to a good headstart.
Hobbyists in Oz often do especially well with native Australian seahorses such as H. breviceps because they can obtain their specimens directly from the breeder without going through any middlemen.
Bottom Line:
Short-Snouted Seahorses (H. breviceps) are the perfect choice for Australian hobbyists with small, cold-water tanks. Aquarists in the US should quarantine newly arrived H. breviceps and use the time in isolation as a grow-out period during which they can be target-fed and lavished with TLC before introducing them to their display tank.
Additional Information (to learn more about Hippocampus breviceps, please consult the following references):
Hippocampus breviceps, Short-head seahorse. 24 Feb. 2004. Fish Base.
<http://www.fishbase.org/Summary/SpeciesSummary.cfm?id=25926&gt;
Warland, Tracy. 2003. Seahorses: How to Care for Your Seahorses in the Marine Aquarium. Port Lincoln, Australia: South Australia Seahorse Marine Enterprises.

Of these minis, only the dwarf seahorses (H. zosterae) are readily available to hobbyists here in the U.S.

Aside from the dwarf varieties, Sindy, you might also consider keeping a pair of the seagoing Shetland ponies better known as Zulu-lulus or Cape seahorses (Hippocampus capensis) in a 12-gallon nano cube. Zulus are a bit larger than the miniature species, but your nano tank could safely house a pair of them, and they are large enough to eat frozen Mysis as their staple everyday diet.

Also known as the Knysna Seahorse, Zulu-lulus (Hippocampus capensis) are well suited for beginners. For one thing, these ponies are just the right size for the average home aquarium and are natural born gluttons — the easiest seahorses of all to feed. They are small seahorses, but they have BIG appetites and will eat most anything and everything the giant breeds do. They are aggressive feeders and, in an impressive display of voracity, even small specimens will unhesitatingly tackle large frozen Mysis that may take them two or three snicks to successfully swallow. A hungry Cape seahorse will often have more than half of a large mysid protruding from its snout, making it look like a sword swallower in mid-performance as it gradually works its gargantuan meal down with a series of mighty snicks! It is an amazing sight to watch an undersized capensis choke down several oversized frozen Mysis in quick succession and come hurrying back for more like it was starving with the tail of the last shrimp still sticking out of its mouth! They are capable of remarkable feats of sheer piggery, and everyone marvels at how rotund they are when they get their first good look at well-fed, captive-bred capensis.

Of course, they love frozen Mysis relicta and are accustomed to eating that as their staple diet, but these chow hounds are not at all picky when they put on the ol’ feed bag. These galloping gourmets also eat rotifers, brine shrimp, amphipods, copepods, red feeder shrimp (Halocaridina rubra), Caprellids — you name it and they’ll eat it. All the usual seahorse foods are taken with relish and these seagoing gluttons don’t seem to mind a bit whether they are live, freshly killed or frozen. They normally feed on nonmotile food in the wild (Garrick-Maidment, pers. comm.), so they thrive on frozen food in the aquarium. In short, feeding these fat little fellas is the last thing the hobbyist has to worry about, and they are much easier to feed than the dwarf seahorses which require live foods!

Hippocampus capensis are fat, pudgy little ponies with a very distinctive appearance. Short and stout, with a portly profile, stubby snouts, big bulging eyes, and perfectly smooth bodies — I can’t decide whether these captivating characters are more cute or more comical looking! They are very unusual for seahorses in that they have no semblance of a crest or coronet whatsoever.

These thick-bodied little seahorses are the perfect size for the home aquarium. They reach a total length of just over 4 inches, and are shipped to you at the modest size of 2-3 inches. That makes them around three times the size of dwarf seahorses — small enough to feel right at home in the average aquarium, yet large enough to make fine display specimens and to eat frozen mysid shrimp as their staple diet. Zulus are the ideal size for a 12-gallon nano tank, Brian. They have proven to be very hardy and easy to breed, and when you’re ready for the challenge of rearing, you’ll find newborn H. capensis are relatively easy to raise, much like dwarf seahorse fry.

However, they are temperate seahorses that prefer cooler temperatures than tropical seahorses. The do best at stable temperatures between a range of 70°F-75°F (22°C-24°C) and don’t tolerate temperature spikes above 75°F well at all. That means you will most likely require an aquarium chiller to keep your 15-gallon tank within the comfort zone for Zulus (H. capensis) at all times, Jonathan.

Fortunately, there are some very affordable mini aquarium chillers that could easily be mounted on your 15-gallon setup. For example, the CoolWorks Ice Probe and Microchiller units are ideal for small tanks (10-15 gallons) and will drop the water temperature up to 6-8°F below the ambient room temperature:

Click here: CoolWorks Ice Probe with Power Supply – Marine Depot – Marine and Reef Aquarium Super Store
http://www.marinedepot.com/md_viewItem.asp?idProduct=CW1111

Click here: CoolWorks Microchiller – Marine Depot – Marine and Reef Aquarium Super Store
http://www.marinedepot.com/md_viewItem.asp?idproduct=CW1131

If you equipped your 12-gallon nano cube with such a chiller so it can maintain temperatures in the 70°F-72°F range at all times, it would be a great setup for a pair of Zulu-lulus (H. capensis), Sindy.

If you want to consider the larger breeds of seahorses such as Mustangs and Sunbursts, then you’ll have to upgrade to a larger aquarium. Let me know if that’s an option for you, and I will be happy to discuss the best type of aquarium for the big boys and how to optimize it to create an ideal environment for your seahorses.

Best wishes with all your fishes, Sindy!

Happy Trails!
Pete Giwojna

Dear Sindy:

Okay, if you’re sure you want to take the plunge, please contact me off list ([email protected]) and I will send you detailed information on keeping and breeding Zulu-lulus (Hippocampus capensis).

It’s good that your are familiar with aquariums from your freshwater angelfish tank, but I have to warn you that saltwater aquariums are quite a bit more demanding than freshwater setups. For example, you will need to obtain a set of basic test kits and monitor the ammonia, nitrite, nitrate, pH and specific gravity routinely and perform regular water changes in order to maintain your water quality parameters at the desired levels. I will explain all of that and a great deal more in the additional information I will provide for you when you e-mail me.

Again, I have to stress that the Zulus do not tolerate heat stress well and require cool aquarium temperatures in order to thrive. This means you will either have to keep your 12-gallon nano cube in an air-conditioned fish room with the thermostat set at 75°F or below, or better yet, invest in a miniature aquarium chiller that can maintain stable water temperatures between 72° F-75°F at all times. You shouldn’t attempt to keep them if you cannot maintain the water temperature in their comfort zone all the time.

Best wishes with all your fishes, Sindy!

Respectfully,
Pete Giwojna