Pete Giwojna
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Re:Help with Seahorse Tank - 2006/03/06 19:19
Dear Jarrett:
That sounds like an excellent system for seahorses! 75 pounds of live rock plus a good sand bed in a 55-gallon tank will provide you with very good denitrification ability to control nitrates as well as all the biofiltration you need. You could even do without the wet-dry filter if necessary; with it, you have a very nice margin for error and increased carrying capacity.
Providing it is small enough, your blue-legged hermit crab should be fine. Tiny hermits that are the size of a shooter marble (including their shell) generally make good tankmates for seahorse and are excellent scavengers. Hermit crabs larger than that, however, become increasingly problematic and should be avoided.
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, 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, but will consume red slime and green algae 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. In your case, Jarrett, with all of that live rock in a 55-gallon aquarium, I would recommend a cleanup crew consisting of up to 50-60 snails and 10-20 micro-hermit crabs in order to control nuisance algae and help assure it never gets a foothold in your tank. The snails and hermits should consist of an assortment of species, as described above, but be sure to include some Astrea snails initially and plenty of Nassarius snails when you're ready to add your seahorses.
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.
Blennies generally make good tankmates for seahorses, but you can never tell for sure. When discussing compatible tankmates for seahorses, it's important to remember that one can only speak in generalities. There are no unbreakable rules, no sure things, no absolute guarantees. For instance, most hobbyists will tell you that small scooter blennies make great tankmates for seahorses and 9 times out of 10 they're right. But every once in a while, you will hear horror stories from hobbyists about how their scooter blenny coexisted peacefully with their seahorses for several months and then suddenly went "rouge" overnight for no apparent reason and turned on the seahorses, inflicting serious damage before it could be captured and removed.
Does that mean that we should cross scooter blennies off our list of compatible tankmates for seahorses? Nope -- it just means that we must be aware that individuals within a species sometimes vary in their behavior and respond differently that you would expect, so there are exceptions to every rule. It's fair to say that scooter blennies generally make wonderful companions for seahorses, but there's always a small chance you might get Satan reincarnated in the form of a scooter blenny. There's no guarantee that adorable scooter you picked out at your LFS because of his amusing antics and puppy-dog personality won't turn out to be the blenny from hell once you release him in your seahorse setup.
I would put your bi-color blenny in much the same category as scooter blennies, Jarrett. It will most likely be fine, but there's a chance it could turn on your seahorses at some point, and you might want to exclude it in order to play it safe. I would feel better about it if your seahorses were established in the aquarium first and then you added the blenny; but as it is, the blenny will have established its territory in your tank and may consider the seahorses intruders when they are subsequently introduced to the aquarium. If he decides to defend his patch of turf, things could get a little dicey. Most of the time, blennies just ignore seahorses, but every once in awhile they will turn on them, and such assaults can be deadly.
Likewise, micro-hermit crabs are generally entertaining additions to an aquarium that do a great job as scavengers and get along great with seahorses, but over the years, I've had a few seahorses that were confirmed crab killers. These particular ponies were persistent hermit crab predators that specialized in plucking the hermits out of their shells and attacking their soft, unprotected abdomens, and they honed their skullduggery to a fine art. They were experts at extricating the crabs and would eat only their fleshy abdomens and discard the rest. Mind you, that was only a few individuals out of a great many Hippocampines, but I could never keep hermit crabs in the same tank with those specific seahorses.
On the other hand, sometimes it's the micro-hermits that are the troublemakers. Most of the time, they coexist perfectly well with their fellow janitors in the cleanup crew. But I've had more than a few tiny hermits with a taste for escargot that persecuted snails mercilessly. These cold-blooded little assassins would kill the snails in order to appropriate their shells. Once they had dined on the former occupant, they would take up residence in their victim's cleaned-out shell! It soon became clear that these killer crabs were driven not by hunger, but by the need for a new domicile. Once I realized they were house-hunting, I found I could curb their depredations but providing an assortment of small, empty seashells for the hermits to use. Colorful Nerite shells are ideal for this.
As far as water movement goes, you'll want a pump that turns over the entire volume of your aquarium at least four to five times an hour. For example, a pump that puts out 300 gallons per hour should not be too strong for an aquarium of 55-gallons. Using a small powerhead or two positioned where they will eliminate dead spots or do the most good for your corals is a good idea. Here are some more guidelines regarding water flow in the seahorse tank from my new book (Complete Guide to Greater Seahorses In the Aquarium):
Water Circulation
Time and time again I find that home hobby tanks have far too little water movement. In my experience, most seahorse setups are chronically undercirculated, a serious mistake for small, closed-systems aquaria, and our pampered pets often suffer as a result. Many hobbyists are overly conscious of the seahorse's inactive life style and limited swimming ability, and have adjusted their flow rates accordingly, resulting in less water movement than desirable. In actuality, seahorses prefer moderate water movement, including some areas of brisk current, providing there are also sheltered spots and some areas of relatively slack water they can move to when desired. Slack water means comparatively low flow, NOT stagnant conditions! Avoid dead spots and stagnant areas at all costs.
I have often discussed this matter with professional divers and collectors who regularly encounter seahorses in the ocean, and they report that the horses are often found where you would least expect them -- well offshore and thriving in areas with powerful currents. For example, here is how Paul Baldassano, a commercial diver in New York who makes his living collecting sea urchins, describes the behavior of his local seahorses:
"In regard to seahorses in the wild, I occasionally see Hippocampus erectus in the wild while SCUBA diving but never in the places where they are supposed to be. I see them in the open sea far from shore and also in areas with large rocks and very strong currents. The last one I saw was in a channel off the south shore of Long Island New York in water about 12 feet deep. The current was so strong that I had to hold on to the rocks so as not to be swept away. This Hippocampus erectus was having no trouble staying there munching on the abundant plankton. Apparently they find places near the rocks where there is no current because as you know they are lousy swimmers. There is also a large population of seahorses in a similar area in another part of the New York shore, but I think it is best not to divulge that location for obvious reasons (Baldassano, pers. com.)."
Neil Garrick-Maidment, a very successful seahorse breeder in the UK, reports much the same thing:
"Whenever I have dived on Seahorse sites I have always been amazed by the currents and tides that this very fragile looking Seahorse lives in. In setting up a tank for them I try to remember the feeling I had in those areas and replicate them. I have now started to use wave surge devices, so that the current in the tank, although strong (they seem to thrive in strong currents) varies in its direction (Garrick-Maidment, Jun. 2002)."
Likewise, David Warland, a fish farmer and commercial seahorse breeder in Port Lincoln, Australia, reports he often finds Hippocampus abdominalis perching on the tuna net enclosures at the farm in deep water:
"The Horses that are around the farms have traveled vast distances over plain sand/mud to get to the farms, which are in at least 20 meters of water, and are miles from the nearest land or shallow water (Warland, pers. com.)."
And Jorge Gomezjurado, the Senior Aquarist at the National Aquarium in Baltimore, recommends the following when it comes to water movement:
"I personally believe that current and water dynamics are very important for Syngnathids. In nature they live in areas with active water movement.(i.e., tides in mangrove lagoons and estuaries, coral reefs, kelp forests, etc.). Why don't give them the same environmental conditions in captivity? Our small tanks (90 gallons) also have large turnovers on an average of 5 gpm (or 300 gph). It is very important that the current is steady and directional constant, which allows the animals to find a good spot to hold and they will not be pulling in different directions all the time."
The point is that, as long as slack-water retreats are available, the greater seahorses can tolerate far more current than most folks suspect and good circulation is as important for a seahorse setup as any other aquarium. I cannot emphasize that enough.
For example, in addition to an external power filter, my SHOWLR system also has a 200 gph powerhead with a sponge pre-filter positioned right near the top for surface agitation and extra water movement, with additional small powerheads used as needed to eliminate any dead spots along the substrate or behind the rockwork. I like to give my seahorses as much current as they can handle without getting blown around.
For your seahorse tank, I suggest the filtration should turn over the volume of the aquarium a MINIMUM of 4-5 times per hour. As long as your seahorses aren't getting buffeted around by the currents, aren't spilling eggs during the copulatory rise, and aren't having difficulty targeting their prey and eating, there's no such thing as too much water movement. Just make sure your seahorses are not getting trapped against overflows and be sure to shield or screen off the intakes for any powerheads or overflows. Powerheads can be turned off or switched off at feeding time, if necessary.
Red kelp and macroalgae in general are excellent in a seahorse tank with lots of live rock. Tree sponges are usually brightly colored (red and orange shades are common) and their shape and texture seem to make them irresistible to seahorses as hitching posts. Very often, all the seahorses in the tank can be found clinging to the same tree sponge together, eschewing other nearby holdfasts that appear every bit as comfy and attractive to human eyes. But as filter feeders, they are often difficult to keep alive in the aquarium. If you have had success keeping live sponges in other tanks, by all means add some tree sponges to your seahorse tank. They will love them! But if you haven't had experience keeping live sponges before, you will be better off excluding them from your seahorse tank, and trying some of the very realistic, lifelike replica sponges that are now available for aquarists in a number of bright colors.
Most soft corals and SPS have relatively weak stings and are suitable for seahorses. This includes zooanthids and colonial polyps in general. I have never kept Nephtheis fascicularis in a seahorse tank personally, but pulsing Xenias are quite compatible so I don't see any reason why you shouldn't try one providing you can meet its aquarium requirements. Here are some additional guidelines that may give you a better idea as to which corals are compatible and which types you should avoid in your seahorse tank:
Setting Up a Reef Tank for Seahorses.
Seahorses typically thrive in the right type of reef system, which provides them with pristine water quality, plenty of roam to roam, and a colorful, natural setting that makes them feel right at home. The multicolored background will keep them looking their best and brightest, and nothing makes a more breathtaking exhibit than brilliant yellow and orange seahorses lazily gliding amidst the lovely corals, polyps and gorgonia in a well-established minireef, much like the butterflies adorning a beautiful flower garden.
But the hobbyist who wants to keep seahorses in a reef system must be willing to make some concessions to accommodate their special needs. For example, the reef keeper must be willing to limit himself to corals and invertebrates that meet the following criteria:
1) Avoid any stinging animals with powerful nematocysts. This means fire corals, anemones, and any corals with polyps that feel sticky to the touch must be excluded. When a seahorse brushes up against them or attempts to perch on them, the nematocysts or stinging cells of these animals can penetrate the seahorse's skin and damage its integument. Needless to say, this causes pain and discomfort and can leave the seahorse vulnerable to secondary bacterial and fungal infections, which may take hold at the site of injury. Beware of large polyped stony (LPS) corals in particular. These include genera such as Catalaphyllia, Cynarina, Euphyllia and Trachyphyllia that have large fleshy polyps which often have tentacles equipped with powerful stinging cells.
2) The corals must be able to thrive with moderate light levels and relatively low to moderate water movement or current. Corals that require overly strong water currents are unsuitable for tanks with seahorses because the seahorses are feeble swimmers and often cannot cope with powerful currents unless there are slack water areas the can retreat to when needed.
3) The corals must be able to withstand being used as hitching posts by the seahorses from time to time; that is, they cannot be so delicate that having a seahorse's grasping tail anchored around them could cause them any harm. For instance, soft corals may retract their polyps when a seahorse perches on them. This can be harmful to their health if it becomes a chronic problem, because the corals rely on their polyps to absorb light and convert it to energy via photosynthesis. Be sure to watch any soft corals and make sure they are not closed up for extended periods. Normally, they adjust to the seahorses' presence and unwelcome attention after a while, and remain contracted only briefly after each contact. After repeated exposures to grasping tails, each such incident elicits a weaker response, so they tend to extend their polyps sooner and sooner after being disturbed.
4) Avoid Tridacna clams and similar bivalve mollusks. Sooner or later a seahorse will perch on them with its tail between the valves and the clam's powerful adductor muscle will clamp down on it like a vise. At best this will be a very stressful experience for the unfortunate seahorse; it can be the devil's own business trying to persuade the stubborn mollusk to release its struggling victim! At worst, it can result in serious injury or permanent damage to the seahorses tail.
5) Beware of unwanted hitchhikers that may have come in on your live rock unbeknownst to you and which can harm seahorses, such as fireworms, mantis shrimp, or Aptasia rock anemones. When setting up a reef system for seahorses, it's a wise precaution to pre-treat your live rock with a hypersaline drip and/or a dose of club soda to eliminate such pests beforehand because they can be very difficult to remove or eradicate once they make themselves at home in your aquarium.
6) Small powerheads can be used to create and direct water currents wherever needed -- just be sure to screen off the intake for the sake of your seahorses. Seahorses tolerate moderate currents very well providing there are sheltered spots and slack water areas they can retreat to when desired.
Soft corals have very little stinging ability and generally make good choices for a modified mini reef that will include seahorses. This includes most zoanthids and mushroom anemones (corallimorpharians) in general. However, as Charles Delbeek cautions, "One notable exception is the elephant ear mushroom anemone (Amplexidiscus fenestrafer). This animal is an active feeder on small fish and will envelope them whole with its mantle then slowly digest them by extruding its digestive filaments into the space created. No small fish are safe with these animals in the tank.". Some of the soft corals that generally do well with seahorses in a low/moderate light, low/moderate flow reef tank with PC lighting are listed below:
Finger Leather Coral (Lobophyton sp.)
Flower Tree Coral - Red / Orange, (Scleronephthya spp.)
aka: Scleronephthya Strawberry Coral, or Pink or Orange Cauliflower Coral
Christmas Tree Coral (Sphaerella spp.)
aka: the Medusa Coral, Snake Locks Coral, or French Tickler
Cauliflower Colt Coral (Cladiella sp.)
aka: Colt Coral, Soft Finger Leather Coral, Seaman's Hands or Blushing Coral.
Toadstool Mushroom Leather Coral (Sarcophyton sp.)
aka: Sarcophyton Coral, Mushroom, Leather, or Trough Corals.
Bullseye Mushroom Coral (Rhodactis inchoata)
aka: Tonga Blue Mushroom, Small Elephant Ear Mushroom (rarely)
Clove Polyps (Clavularia sp.)
Stick Polyp (Parazoanthus swiftii)
Green Daisy Polyps (Clavularia sp.), Indonesia
Orange & Green Colony Button Polyps (Zooanthus sp.), Fiji
Pulsing Corals (Xenia spp.)
Red Ricordea (Ricordea sp.), Indonesia, occasionally Solomon Islands
Lavender Hairy Mushroom (Actinodiscus sp.), Tonga
Pimpled Mushroom (Discosoma sp.), Indonesia
Purple Gorgonians
Other low light corals that should be suitable include genera such as Cynarina, Scolymia and Trachyphyllia, as well as non-photosynthetic gorgonians such as Subergorgia and Didogorgia, and perhaps wire corals such as Cirripathes spp.. However, supplemental feedings of zooplankton may be required to maintain these corals in good health.
The small polyped stony (SPS) corals generally have weak stings that should not pose a threat to seahorses. Depending on conditions in the tank, SPS corals such as Acropora, Montipora, Pocillipora, Porities, Seriatopora and Stylophora can be tried at your discretion.
Yes, I think it's a wonderful idea to establish a refugium in a sump for your 55 gallon seahorse system! The way I would do it is to set up a dual-chamber sump beneath the tank and fill one chamber of the sump with macroalgae to serve as the refugium. Seed it with starter cultures of copepods, Gammarus, Volcano shrimp (Halocaridina rubra) and the like, and just let nature take its course. Keep the refugium either on an opposite photoperiod to the main tank or illuminate it 24 hours a day.
There are many advantages to adding a sump/refugium to your seahorse setup. For starters, it increases the overall water volume of your system with all the benefits that implies. A good-sized sump can easily double your carrying capacity, increasing your safety margin accordingly. It makes an ideal place to put a protein skimmer, heater(s), air stones, and other equipment so they don't have to be hidden in the display tank. (A well-designed sump does a great job of trapping and eliminating the microbubbles emitted from skimmers and preventing them from entering the aquarium, and provides an excellent way of increasing the aeration/oxygenation, which is so important for a seahorse setup.) It's the perfect place to perform additional mechanical and chemical filtration, tailoring the filter media to meet ones exact needs, or to add a calcium or nitrate reactor or even a Deep Live Sand Bed (DLS to your seahorse setup. Because the sump is a large body of water separated from the aquarium itself, it facilitates water changes, dosing supplements, adding top-off water to the tank and other maintenance tasks, all of which can be carried out in the sump without disturbing the main tank or stressing its inhabitants. Entire sections of the mechanical filtration can be cleaned at one time without affecting your primary biofilter, and water changes can be performed gradually without causing stress to the fish or invertebrates. A sump/refugium can also be used to grow a lush bed of macroalgae using a reverse lighting cycle to stabilize the pH and absorb wastes.
To take advantage of these benefits, I suggest adding a two-chambered sump to your tank. This can be accomplished by installing a perforated tank divider across the width of the sump, thereby separating it into two isolated compartments. One side accommodates all of your equipment (in-sump skimmer, return pump, heaters, titanium grounding probe, UV sterilizer, etc.) while the other side can be used to establish a deep live sand bed (DLS with plenty of Caulerpa. The DLSB/Caulerpa side serves as a refugium and will soon become populated with countless critters (copepods, Gammarus and other amphipods, larval crustaceans, etc.). With the Caulerpa acting as an algal filter and the anaerobic layers of DLSB providing denitrification, the aquarist never need be concerned about nitrates or nuisance algae with this type of sump/refugium.
In addition, the biological refugium/sump can be maintained on an opposite light cycle to the main tank to offset the daily fluctuations in pH, photosynthesis, dissolved oxygen/carbon dioxide, and redox levels that otherwise occur in the aquarium. Daily variances in chemical, physical and biological phenomena are a fact of life in aquaria, linked to the light and dark cycles and the diurnal rhythms of captive aquatic systems. As one example, the pH of aquarium water typically peaks after the lights have been on all day at a maximum of perhaps 8.4, only to drop to low of below 8.0 overnight. This is related to photosynthesis and the fact that zooanthellae and green plants consume CO2 and produce O2 when there is adequate light, but in essence reverse that process in the dark, consuming O2 and giving off CO2. Redox levels, available calcium and other water quality parameters are affected in similar ways. Needless to say, these variations are far greater is a small, closed-system aquarium than they are in the ocean, so it's beneficial to minimize such fluctuations by reversing the photoperiod in the main display and the sump/refugium. This is easily accomplished by timing the lighting in the sump so that the bed of macroalgae is illuminated after dark when the lights on the display tank are off, and vice versa. Just use alternating timers on the main tank and the refugium tank so that when one is on, the other is off. Voila! Just like that the roller coaster ride is over: no more daily fluctuations in pH or highs and lows in calcium levels, oxygen minima, or peaks and valleys in redox potential.
Because it is separate from the main system yet shares the same water, the sump/refugium can also be used as a nifty acclimation tank for new arrivals or a handy isolation tank for separating incompatible specimens. For seahorse keepers, the refugium compartment of a divided sump or dual chamber sump makes an ideal grow-out tank for juvenile seahorses that have outgrown their nurseries but are still too small to be kept in the main tank. A dual-chamber sump is a very versatile design that lends itself to multiple purposes. Use your imagination.
Best of luck with your new seahorse setup, Jarrett! It sounds like it's shaping up to be an outstanding system!
Happy Trails!
Pete Giwojna
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