Welcome to the group!
Doing your homework ahead of time, researching the needs and requirements of seahorses, reading up on them in advance, and asking a lot of questions before you take the plunge is certainly the right approach to seahorse keeping! It’s always a pleasure to help hobbyists who are so keen on getting things right and I would be happy to help you get started off on the right foot.
There are several fairly recent books about seahorses available that would be helpful for a beginner. I would say the most useful of these is "How to care for your Seahorses in the Marine Aquarium A Stable Environment For your Seahorse Stable" by Tracy Warland. Either of Neil Garrick-Maidment’s two latest books, "Seahorses: Conservation & Care" or the "Practical Fish-Keeper’s Guide to Seahorses" would also be good choices. And "Seahorses: Complete Pet Owner’s Manual" by Frank Indiviglio is another worthwhile book for someone new to seahorses. If you only get one of these books, make it Tracy’s guide on "How to Care for Your Seahorses in the Marine Aquarium."
You can order all of these books online from Jim Forshey at the Aquatic Bookshop (http://www.seahorses.com/index.shtm) or from Amazon.com and the other major booksellers.
Keep an eye out for my new book as well. It is called the "Complete Guide to the Greater Seahorses in the Aquarium, TFH Publications" and should be coming out sometime later this year. It is far more detailed and comprehensive than the other books mentioned above, and is considerably longer than all four of them put together.
Nano cubes are compact and convenient, but they are not the best choice for seahorse keepers. A number of our other members have tried fairly large (24-gallon) Nano cubes for seahorses and found them to be unsatisfactory.
Other Club members who have tried the 24-gallon Nanocube for their seahorses report that it is quite unsuitable right off the shelf and requires substantial modifications in order to make it marginally useful for seahorses. For starters, the pump needs to be upgraded, it has no means of filtration so you must provide a biofilter of some sort, and small powerheads should be added to eliminate dead spots and improve the circulation. Even with those modifications, you must stock the Nanocube sparingly, be very careful to avoid overfeeding, and practiced an accelerated maintenance schedule, including weekly water changes.
So I would not recommend a Nancube for a beginner who is new to marine aquariums. They are best reserved for more experienced aquarists who are accomplished do-it-yourselfers and are interested in keeping specimens other than seahorses. All things considered, Kim, I think you’ll be better served with a standard aquarium than a Nancube.
Small seahorse species such as Zulu-lulus (Hippocampus capensis) might do well in an aquarium of around 24-gallons, but if you are interested in any of the larger breeds of seahorses, such as Hippocampus erectus, the smallest aquarium I would suggest is a 29-gallon tall tank. And for a beginner, I would recommend starting out with a larger aquarium of around 40-50 gallons, since it is not until you reach a water volume of about that size that you begin to see real benefits in terms of the greater stability a marine aquarium needs. Those larger tanks will provide a much more comfortable margin for error for someone who is new to seahorses.
But that doesn’t mean that you need to piece together an aquarium systems from its component parts yourself, Kim. You can purchase an aquarium system with all the filtration and equipment you need built right in, which often simplifies things for a beginner. For example, the SeaClear System II Aquariums come equipped with a wet/dry filtration system that accommodates biological, chemical and mechanical filtration media, as well as space for a heater and SeaClear Protein Skimmer, all neatly contained and hidden behind a false back that extends a few inches out from the rear of the tank so that none of the equipment shows at all.
That’s an excellent filtration system for the seahorse tank! As far as biofiltration goes, wet/dry trickle filters are probably the most desirable units for the seahorse keeper after live rock filtration., and you would have both in the tank you are planning, Kim They are top-of-the-line units that feature a thin film of water trickling over filter media with an ultra-large surface area, thereby allowing maximum air-water contact. This provides excellent oxygenation with efficient offgassing, which is very important for seahorses. It helps keep dissolved oxygen levels high, CO2 low, and effectively prevents gas supersaturation, which can sometimes contribute to serious problems (gas bubble disease) for our aquatic equines. As an added benefit, wet/dry trickle filters can also support a tremendous population of aerobic nitrifying bacteria that provide remarkable biological filtration, which gives these systems excellent carrying capacity and a decent margin for error for beginners. In addition, SeaClear System II has compartments built right in to accommodate a protein skimmer, heater, and chemical/mechanical filtration.
Best of all, the whole filtration system is built right into the aquarium as an integral part of the whole. There’s nothing to install and the maintenance consists of rinsing and/or replacing the prefilter as needed. This would be a very easy system for beginners to set up and maintain.
And having all the filtration and equipment safely hidden away behind that false back is another big plus the seahorse keeper. Not only does it look nice, there are no cords, airlines, siphon tubes, or heaters hanging in the tank for seahorses to perch on high up in the water column. That makes it safer for the horses — no chance of heater burns and less risk of gas bubble disease from hanging high near the surface where there’s less hydrostatic pressure. Plus the filter intakes are all walled off from the seahorses — no way a curious seahorse will get sucked up against them or have its tall drawn into an intake tube.
So I would suggest that you look for a SeaClear System II Aquarium, or a similar ready-made aquarium system (the brand name is not important), of sufficient size to provide you with a comfortable margin for error. If you can afford it, the Deluxe Sea Ranch offered by Ocean Rider is a 50-gallon system that would fit the bill nicely.
The basic plan you’ll outlined sounds fine. Live rock and live sand are good choices — in fact, my preferred setup for keeping horses is a "Seahorses Only with Live Rock" or SHOWLR tank — and I think Mustangs (H. erectus) are the ideal choice for your first seahorses. Neon gobies are suitable companions for seahorses and those baby horseshoe crabs are certainly very cute and interesting. It is especially fascinating to watch them swimming, which they accomplish upside down by flapping their gill books and sculling busily along with their many pairs of legs all paddling in unison.
However, you will never see the horseshoe crabs in an aquarium with a sand substrate. Shortly after you introduce them to your aquarium, they will burrow into the sand in search of marine worms and other microfauna and burrowing organisms that they feed on, and you’ll rarely ever see them above ground again. They are best appreciated in bare-bottom tanks or an aquarium with just a thin covering of calcareous gravel.
Once your aquarium has cycled, and the ammonia and nitrite levels have dropped to zero, it’s a good idea to introduce your sanitation engineers before anything else, Kim. I prefer a cleanup crew consisting of a mixture of assorted snails and micro hermits (heavy on the snails but light on hermits) at a density of up to 1-2 janitors per gallon. The snail assortment may include bumble bee snails, trocha snails, margaritas, Astrea and Cerith snails, red foot Moon snails, etc., but especially Nassarius snails.
Nassarius snails are terrific detritivores and amazingly active for snails. They’ll bury themselves until they detect the scent of something edible, and then erupt from the sand and charge out to clean it up.
For best results, Astrea sp. snails should go in the tank as soon as the ammonia and nitrite levels are down to zero in order to keep nuisance algae from gaining a foothold in your tank. Introduced as soon as possible to a new aquarium that has reached this cycling phase, Astrea snails effectively limit the development of all microalgae. In other words, they are good at eating diatoms, and will consume red slime and green microalgae as well.
For hermits, I like a combination of Dwarf Blue-leg (Clibanarius tricolor), Left-handed (Calcinus laevimanus), Mexican Red Legged Hermits (Clibanarius digueti) and above all, Scarlet Reef hermit crabs (Paguristes cadenati), which are my personal favorites.
The Scarlet Reef Hermit Crab (Paguristes cadenati) is a colorful micro-hermit that’s a harmless herbivore. So cannibalism isn’t a concern at all for these fellows, nor are they likely to develop a taste for escargot. As hermits go, most of the time the Scarlet Reefs are perfect little gentleman and attractive to boot. I even use them in my dwarf seahorse tanks. Best of all, they eat all kinds of algae, including nuisance algae such as red, green and brown slimes, as well as green hair algae.
Stick with hermits like the above, which are known as micro hermits because they start out tiny and stay small. Avoid Anomura species of hermit crabs no matter how small they are, however, because they will kill Astraea snails to obtain their shells.
A mixture of the snails and micro hermits listed above provides a very good balance of herbivores, omnivores, and detritivores that are all active scavengers and completely compatible with seahorses. They will clean up meatier leftovers such as frozen Mysis as well as helping to control nuisance algae.
After the tank has been up and running for several months, you can add a few large Peppermint Shrimp (Lysmata wurdemanni) and/or Scarlet Cleaner Shrimp or Skunk Cleaner Shrimp (Lysmata amboinensis) to complete your cleanup crew and add a touch of color and activity to the tank.
Peppermint shrimp (Lysmata wurdemanni) are a favorite with seahorse keepers because they eat Aiptasia rock anemones, and both the peppermints and Scarlet cleaner shrimp (Lysmata amboinensis) will perform another useful service by grooming the seahorses and cleaning them of ectoparasites. As an added bonus, they reproduce regularly in the aquarium, producing swarms of larval nauplii that the seahorses love to eat.
Just remember, it is important to select the largest possible cleaner shrimp for your seahorse tank(s). Seahorses will actively hunt small cleaner shrimp and they are quite capable of killing shrimp that are far too big to swallow whole, so the cleaners need to be large enough that they are not regarded as potential prey.
Another thing to keep in mind when introducing cleaner shrimp to your aquarium is that they are more sensitive to water quality and rapid changes in pH, temperature, or salinity than fishes are, meaning the shrimp need to be acclimated more carefully and gradually. Whereas drip acclimation should be avoided for seahorses that have been on the shipping bag for 24 hours or more, it is the perfect way to acclimate delicate shrimp from your LFS. They will do best it drip acclimated to the new aquarium over a period of several hours to allow them to adjust to any differences in the water parameters very gradually.
Shrimp that are introduced to a new aquarium too abruptly will not flourish and are liable to die within a day or two from the stress of acclimation, unable to adjust to any significant differences in pH or salinity, or they simply fail to thrive and expire a week or two later for no apparent reason. If the shock is too great, they will autotomize, dropping legs, claws and/or antennae immediately upon being introduced to the new aquarium conditions.
In short, Kim, after your tank has finished cycling, I would install your cleanup crew as soon as possible. The snails and micro-hermit crabs are interesting to watch in their own right. When the aquarium has stabilized after a couple of months or so, I would consider adding some decorative shrimp rather than the horseshoe crab. Cleaner shrimp are much more colorful and useful in an aquarium, and will remain out in the open where you can enjoy them much more so than the horseshoe crabs, which will bury in the sand.
Next I would add your seahorses. For best results, only after you have gained a little seahorse savvy and some invaluable personal experience experience working with the seahorses should you consider adding other suitable fishes that are compatible tankmates.
There have been several other threads on the Ocean Rider Club discussion board at seahorse.com from hobbyists who were just starting out with seahorses that you should also find to be of interest. They discuss setting up an ideal system for seahorses, filtration, feeding, lighting, circulation and so on. I’ve provided links to those discussions for you below, so please check them out. I think they will answer many of your questions about keeping seahorses:
Re:Hello, newbie here! – O http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,1004/catid,2/
Re: Guidance on Keeping Seahorses:
Re: New to seahorses and I have lots of questions!
Re: Tank set-up advice
Please let us know if you have any other questions that haven’t been covered in those previous discussions, Kim!
Let me know when you have decided on an aquarium and are ready to cycle it, and I’ll send you complete step-by-step instructions explaining how to cycle the tank and establish the biofiltration. Or you can contact me off list and I’ll be happy to send you more detailed information on picking out and setting up a new aquarium for seahorses that is too lengthy for a forum such as this. You can reach me at the following email address: [email protected]
Best of luck with your ongoing research on keeping seahorses, Kim!