Re:Hello, newbie here!

Pete Giwojna

Dear Saoirse:

Welcome to the Club! Yes, you are absolutely correct — working with hardy, easy to feed, captive-bred-and-raised seahorses will greatly increase your chances of success with these amazing aquatic equines.

A 35-gallon aquarium is a decent sized to start with, but if you are new to seahorses then I would suggest upgrading to a tank in the 40-50 gallon range. Unless you will be keeping one of the miniature breeds of farm-raised seahorses, such as Hippocampus zosterae, H. breviceps, or H. tuberculatus, it’s best to start with the largest aquarium you can reasonably afford and maintain (the taller, the better). In general, a tank of at least 40 gallons (150 L) is preferable since that’s the size when one begins to see significant benefits in terms of the greater stability a larger volume of water can provide. An aquarium of 40-gallons or more will be more resistant to overcrowding and to rapid fluctuations in temperature, pH, and salinity than smaller setups. The larger the aquarium the larger the margin for error it offers the aquarist and the greater the benefits it provides in terms of stability.

It is equally desirable to select an aquarium at least 20-inches high when keeping the greater seahorses. They need the vertical swimming space to perform their complex mating ritual and successfully complete the egg transfer, which is accomplished while the pair is rising through the water column or drifting slowly downwards from the apex of their rise. If the aquarium is too shallow, eggs will be spilled during the transfer from the female to the male’s brood pouch, and mating becomes increasingly difficult or impossible below a certain minimum depth. A tall aquarium can also help protect the seahorses from depth-related health problems such as bloated pouch and certain forms of Gas Bubble Disease.

As for which seahorses are best suited for beginners, I agree with Leslie in that regard: you can’t go wrong with Mustangs (Hippocampus erectus), Sydneys (H. whitei) or Zulus (H. capensis) depending on whether you fancy large, medium, or small seahorses respectively. Or if you prefer a mixture of sizes and types, then all three species can be kept together providing you hold the water temperature around 72°F

The suggested stocking density for Mustangs (H. erectus) is one pair per 10 gallons of water. For Sydney seahorses (H. whitei), it is one pair per 8 gallons. And you should limit yourself to one pair of Zulus (H. capensis) per 5 gallons. But as always, if you’re new to seahorses, you will be better off keeping your stable under stocked in order to provide a margin of error while you learn the ropes with these amazing aquatic equines. And when the big day comes and you are finally ready to begin filling up the old corral with thoroughbreds, be sure to remember the three golden rules that should always guide your actions when stocking your seahorse setup:

I. Under stocking is ALWAYS better than over stocking. Always! That is the one immutable law that governs the seahorse-keeping universe, and if you violate it, the aquarium gods will exact swift and terrible retribution!

II. When in doubt, under stock. Don’t push your luck! If you have any doubt whatsoever as to whether or not your system is running at capacity, it probably is. In such a situation, you MUST err on the side of caution.

III. Don’t mess with success! If your seahorse setup has been running smoothly and trouble-free for a prolonged period at it’s present level of occupancy, try to resist the temptation to increase your herd. Why risk upsetting the balance in a system that has settled into a state of happy equilibrium? Rather than risk overcrowding an established tank, consider starting up a new aquarium when the urge to acquire some new specimens becomes overwhelming.

When stocking your aquarium, consider these golden rules to be your commandments. Obey them, and your system should flourish. Surely goodness and mercy shall follow thee all of thy days. Break them, and you will soon find yourself teetering on the brink of disaster. Abandon all hope ye whom embark down that dark road to ruin.

Tropical Tankmates.

I have prepared a list of suitable fishes and invertebrates that generally make compatible tankmates for tropical seahorses below. Avoid fin nippers and aggressive, territorial fish that would be inclined to bully or physically abuse the seahorses, such as damsels, most clownfish, triggerfish, angels, puffers, cowfish and the like, as well as any predatory fishes that are large enough to swallow a seahorses, such as lionfish, anglers, sargassumfish, rays, large groupers and morays. For best results, other fishes that would not persecute the seahorses in any way should also generally be excluded because they are active, aggressive feeders that would out-compete the seahorses for food. This includes most butterflyfish, tangs, and wrasse. Stinging animals like anemones and jellyfish are unsuitable, as are other predatory invertebrates such as lobsters, mantis shrimp, certain starfish and most crabs.

Clownfish meet many of the criteria for suitable tankmates, but should generally be regarded with caution (Giwojna, Feb. 2004). Most species, such as Tomato Clowns (Amphiprion frenatus), Maroon Clowns (Premnas biaculeatus), and Skunk Clownfish are surprisingly aggressive and territorial, and should be shunned on that basis. Others do best when keep with anemones, which are a threat to seahorses. All clownfish are prone to Brooklynella and Marine Velvet (Amyloodinium), and should be considered Ich (Cryptocaryon irritans) magnets as well (Giwojna, Feb. 2004). The only species I would recommend as companions for seahorses are Percula Clowns (Amphiprion percula) and False Percula Clownfish (A. ocellaris), and then only after a rigorous quarantine period (Giwojna, Feb. 2004). Captive-bred specimens are best.

In short, fishes that are suitable as companions for seahorses must be docile, nonaggressive specimens, which are fairly deliberate feeders that won’t out-compete them for food. Some good candidates include:

Anthias (assorted Mirolabrichthys, Pseudanthias, and Anthias sp.)
Firefish Goby (Nemateleotris magnifica)
Purple Firefish Goby (Nemateleotris decora)
Gobies (assorted small species)
Neon Goby (Gobiosoma oceanops)
Assessors (Assessor spp.)
Midas Blenny (Ecsenius midas)
High Hats (Equetus acuminatus)
Marine Betta (Calloplesiops altivelis)
Banggai or Banner cardinals (Pterapogon kauderni)
Flame cardinals (Apogon pseudomaculatus)
Pajama cardinals (Apogon nematoptera)
Pipefishes (assorted small species)
Percula clownfish (Amphiprion percula)
False percula clownfish (Amphiprion ocellaris)
Royal Grammas (Gramma loreto)
Blackcap Basslets (Gramma melacara)
Green Chromis (Chromis viridis)
Longnose Hawkfish (Oxycirrhites typus)
Six Line Wrasse (Psuedocheilinus hexataenia)
Flasher Wrasse (Paracheilinus sp.)
Fairy Wrasse (Cirrhilabrus spp.)
Scooter Blennies (Synchiropus spp.)
Green Mandarin Goby or Dragonet (Pterosynchiropus splendidus)
Psychedelic Mandarin Goby or Dragonet (Pterosynchiropus picturatus)
Orchid Dottyback (Pseudochromis fridmani) – avoid other Pseudochromis species!

Good inverts for seahorses include decorative cleaner shrimp like those listed below:

Peppermint Shrimp (Lysmata wurdemanni)
Scarlet Cleaner Shrimp or Skunk Cleaner Shrimp (Lysmata amboinensis)
Fire Shrimp (Lysmata debelius)
large ornamental snails (living sea shells) such as the following:
Tiger Cowry (Cypraea tigris)
Deer Cowry (Cypraea cervus)
Assorted Feather Dusters (Sabellastatre magnifica, Sabella sp.) whose colorful crowns resemble gaily-colored parasols.

By no means is this intended to be a comprehensive compilation. It is intended merely to give the hobbyist an idea of the types of fishes and inverts that generally make suitable tankmates for seahorses. But there are many more seahorse-safe fish and invertebrates that could have been added to the list, and no doubt many aquarists would disagree about some of the species that have been included.

Be that as it may, there are two precautions that should always be observed when contemplating keeping seahorses with other fishes:

(1) All fishes that are intended as tankmates for seahorses MUST be quarantined first without exception. For the same reasons we discussed earlier with regard to wild-caught seahorses, any fish you bring home from your LFS is a potential disease vector for all manner of nasty pathogens and parasites, and you need to take every possible precaution to prevent these from being introduced to your display tank.

(2) If you are new to seahorses, you will be much better off sticking to a species tank rather than attempting to keep them in a mixed community. Beginners are well advised to keep things as simple as possible while they learn the ropes, and introducing other fishes and invertebrates tankmates complicates feeding and carries new risks that inexperienced seahorse keepers are ill-equipped to cope with. Get some firsthand experience with seahorses before you consider adding any tankmates other than a cleanup crew.

As with most marine fishes, you find that caring for seahorses is largely a matter of providing them with optimal water quality, a nutritious diet, and a suitable stress-free environment. The aquarium temperature should be stable (no more than a gradual 2°F change in temperature daily) and held in the range of 72-75°F. A temperature of 72°F should be ideal for the species you are considering. The salinity or specific gravity of the water should be held stable anywhere in the 1.022-1.025 range. Keep the pH of the aquarium water between 8.2-8.4 (and a good dual-phase marine buffer if it falls below that range). The ammonia and nitrite levels should be zero at all times in the nitrate levels should be held below 20 ppm.

If you don’t already have them, you will need some saltwater test kits to monitor conditions in your aquarium and keep track of the water quality. The basic test kits you’ll need to keep track of the aquarium parameters are ammonia, nitrite, and nitrate, plus a hydrometer to check specific gravity and an aquarium thermometer. You’ll need to get separate test kits for ammonia, nitrite, and nitrate, and I recommend fasTest or Salifert kits for saltwater. I also like the SeaTest hydrometers–convenient, easy to read, and reliable.

A test kit to measure the levels of dissolved oxygen is also useful for seahorse keepers. The Tetra Oxygen Test Kit (TetraTest 02) is a good liquid reagent test kit for fresh or saltwater with simple color scales for comparing readings that tests for 02 in the range of 2-14 ppm (the optimum dissolved O2 level is 6-7 ppm). It will cost you between $8.50 to $14 depending on where you shop and should be available at any well-stocked LFS. Salifert also makes a nice 02 Test Kit (their 02 Profi-Test) that will run you about $20.

Seahorses prefer low-to-moderate light levels, including both some brightly lit areas they can move into what they want to bask in the light and some shaded areas they can retreat to when they would like to get out of the light. A simple aquarium reflector with standard fluorescent tubes is fine.

Seahorses don’t like overly strong currents that they have to fight while swimming or that whisk food past them too fast to scrutinize, target, and eat, but good circulation is as important in a seahorse setup as any other aquarium. You must avoid dead spots, where there is no water movement at all, without producing currents that are too overpowering.
In general, seahorses prefer moderate water movement, including some areas of relatively brisk current, providing there are also plenty of 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.

Testing Water Quality

After the tank is established, as a general rule, it’s a good idea to test your basic water quality parameters once a week if all is well. And, of course, you’ll want to break out your test kits at the first sign of trouble. Here are some basic aquarium management guidelines to follow when servicing the seahorse tank:

Cleaning and Maintenance.

Once established in a well-designed aquarium, keeping seahorses successfully becomes largely a matter of providing them with optimum water quality and a nutritious diet. Good water quality is a direct result of proper cleaning and maintenance. Get a set of new 5-gallon plastic buckets, a siphon hose designed for the aquarium, gravel washer, algae scrapers, dip tubes and nets to assist you with your regular aquarium chores. Set these aside for aquarium use only (indeed, it’s a good idea to have a separate set of such aquarium tools just for your seahorse setup, in order to avoid cross-contamination with other tanks).

Daily Maintenance:

Your daily chores begin with feeding your livestock and cleaning up afterwards. Considering that captive-bred seahorses are trained to eat enriched frozen Mysis as their staple diet, proper feeding means assuring that each of your steeds gets it’s fill without overfeeding them, and that you clean up any leftovers promptly. Use of a feeding station, target feeding slow eaters, and a good cleanup crew are all helpful in that regard, as will be discussed in detail in the next chapter.

Dip tubes, basters, and long-handled nets are useful for gleaning leftover Mysis, and while you’re at it, you should also take a moment to police the bottom for any debris, accumulated plant matter, and fecal pellets. Promptly removing such waste materials, before they breakdown and enter the nitrogen cycle, will go a long way toward towards assuring good water quality, controlling nitrates, and keeping your substrate clean.

When feeding your seahorses, take advantage of this opportunity to conduct a close-up, daily inspection of every specimen in his tank. These detailed examinations are perhaps the most important of the seahorse keeper’s daily chores, yet many aquarist ignore this vital task altogether. Such inspections make it difficult not to notice any subtle changes in my seahorse’s appearance or behavior that might signal impending problems with disease or the water chemistry. That’s extremely important, since seahorses hide their illnesses so well (Indiviglio, 2002), and the sooner such potential problems are detected, the easier they are to cure or prevent. Due to there sedentary lifestyle, it can be difficult to detect when a seahorse has a problem. The first signs of trouble are often very subtle: an increase in respiration, a decrease in eye movement or appetite, a localized change in pigmentation or the appearance of a tiny nodule the size of a goosebump or mosquito bite.

So take a moment to enjoy the show when feeding your seahorses. Make sure they all show up for mess call, are acting normally, and have a well-rounded abdomen when they’re done eating. Watch them swim and move around as they answer the dinner bell. Make sure they’re not having difficulty maintaining their equilibrium or experiencing any buoyancy problems. Observing their behavior at mealtimes makes it hard to miss when one these chowhounds is off its feed, which is often an excellent early indicator that something’s amiss in the aquarium.

Likewise, keep a close eye on the health of any sessile animals and benthic invertebrates in the tank, such as sponges, sea cucumbers, tunicates, snails and starfish. It can be difficult to determine if inactive animals like these are alive and well or on their way out, and nothing fouls a tank faster than the undetected death of a large turban snail or sea star or sponge. This is especially important if you’re keeping your seahorses in a modified reef tank. One neglected mushroom coral turning to mush can cause an ammonia spike that imperils all the other invertebrates and thus threatens the entire tank.

Make a quick check of the electrical equipment as well. See that the aquarium temperature is holding where you want it to assure that the heaters are working properly. Double check the filters, pumps, powerheads and lights to make sure they are all operating and producing normal flow rates. Decreased flow could indicate a malfunction or indicate that the filter is dirty and clogged and needs to be cleaned. Make sure the protein skimmer is doing its job: adjust the bubble column if needed and empty the collection cup if necessary.

Checklist of Daily Chores:
· Feeding(s).
· Daily inspection of livestock.
· Temperature check.
· Equipment check.
· Empty the collection cup on your skimmer.
· Clean up leftovers and debris.

Weekly Maintenance.

It’s important to check the water level of the aquarium at least once a week. It will drop steadily due to evaporation, increasing the salinity of the aquarium water in the process. If the water level falls too far, it can break the siphon on return tubes and intakes, filters can become airlocked, and protein skimming may be disrupted. Remember, only the water evaporates; all of the salts and minerals it contains are left behind. When replacing the water lost to evaporation, top off the tank with freshwater, not saltwater. The water used to top off the tank should be treated to remove chlorine and chloramines, aerated, and adjusted to roughly the same temp as the aquarium water.

Salt creep and condensation of aquarium water on the underside of the aquarium cover can led to the build up of salt deposits on the glass, light fixture, hood or lid of the tank, or on various pieces of equipment. Not only is this unsightly, it can drastically reduce the light level in the aquarium and cause electrical shorts. It’s a good idea to remove these crusty accumulations periodically by cleaning them off once a week or so with a damp cloth or sponge reserved for aquarium use only.

The aquarium glass itself should likewise be cleaned at least once a week. Algae scrapers or algae sponges (often mounted on strong magnets) can be used to clean the interior of the tank. Different tools are available for cleaning glass tanks and easily scratched acrylic tanks, so be sure you use the right kind for your setup.

The exterior aquarium glass can be cleaned using plenty of elbow grease and crumpled up newspapers. Surprisingly, old newspaper has just the right texture, consistency and absorbency to do a marvelous job of polishing aquarium glass, and something about the newsprint prevents streaking of the glass on the viewing surfaces. Slightly damp newspaper is perfect for keeping the aquarium glass looking immaculate.

It’s also advisable to break out your test kits on the weekends and check the key measurements of your water chemistry. Test the pH for sure since it inevitably declines over time. A significant drop in pH may require the addition of a buffer to correct it or indicate the need for a water change. Get out your hydrometer and test the specific gravity. It may have fallen due to salt creep or the formation of salt stalactites, or it may have risen due to evaporation. Adjust it accordingly. Nitrate levels will rise steadily over time so they must be monitored as well. We want to keep nitrates below 20 ppm (lower if your setup is a modified reef system). Many systems rely primarily on water changes to control nitrates, and a persistent rise in nitrate levels calls for a water exchange.

Checking your dissolved oxygen level can be especially revealing. A decrease in O2 is often a harbinger of trouble, and it thus alert the aquarist to a dangerous situation while there’s still time to correct it. For instance, an unexpected drop in O2 can be an indication of overcrowding or overfeeding, or it can be a sign that the tank and/or the filters are overdue for a good cleaning, or reveal the need for better circulation and surface agitation. Take appropriate measures to correct the problem, until the oxygen readings are back to normal (6 – 7 ppm is optimal).

The aquarist should also be diligent at harvesting any fast-growing Caulerpa in the tank on a regular basis. Periodically removing a portion of the Caulerpa is a very effective way to export nitrates, phosphates, and other nutrients from the aquarium. When pruning back or harvesting the Caulerpa, take care not to cut or sever the plants. Cutting it or breaking off too many fronds causes the Caulerpa to leach undesirable substances from the cut or broken ends into the water. Not only is this bad for the water quality, it can sap the colony and perhaps trigger one of the dreaded "vegetative events," during which the main colony enters its reproductive phase and releases its reproductive products. The best way to harvest the Caulerpa is to carefully extract unbroken continuous fronds. The idea is to thin out convenient strands of Caulerpa from the colony, gently pulling up entire fronds, intact and unbroken. This is a wonderful way to remove nitrogenous wastes (which the plants utilize for growth like fertilizer) from the aquarium, and if done consistently, it will prevent the colony from going sexual.

Checklist of Weekly Chores:
· Top off tank with freshwater to replace water lost to evaporation.
· Remove salt buildup.
· Clean aquarium glass (inside and out).
· Check basic water quality parameters:
(pH, specific gravity, nitrate, etc., and especially dissolved O2)
· Harvest Caulerpa.
· Partial water change (if indicated).

Checklist of Monthly Chores:
· Clean filters/replace filter pads/rinse and recharge or replace chemical media.
· Perform partial water change.
· Vacuum uppermost layer of substrate (top 1/2 inch).
· Clean aquarium decorations as needed.

Corals and Aquascaping

When aquascaping with your artificial corals, bear in mind that seahorses don’t need a great deal of open bottom space. They are vertically oriented fish and need vertical swimming space in the upper half of the water column (for mating and the egg transfer) more than bottom space.

A certain amount of complexity is desirable in a seahorse setup. For example, a tank with too few attachment sites and hitching posts is a stressful environment for seahorses, as is a sparsely decorated aquarium that leaves these secretive animals feeling vulnerable and exposed. Such sterile environments are commonplace when seahorses are being maintained under laboratory conditions. A Spartan setup facilitates feeding, water changes and maintenance, in general, but it can adversely affect the behavior of the inhabitants and may even prevent captive seahorses from breeding.

Hippocampus relies on camouflage and remaining hidden for its very survival. Seahorses can thus become distressed and agitated if their tank is too barren to provide adequate cover. This is particularly true during courtship and mating when the increased activity level and heightened coloration make them highly conspicuous and vulnerable, and breeding may be severely inhibited under these conditions.

A recent research project that studied the behavior of captive Cape seahorses (Hippocampus capensis) recently confirmed the need for a certain level of complexity in any setup for seahorses (Topps, 1999). The study found that seahorses display more "natural" behavior when they are provided with an elaborate, structured environment that includes a number of different microhabitats (Topps, 1999). These findings are another indication that a sparse setup with inadequate shelter can inhibit the behavior of captive seahorses.

Your seahorse setup should therefore include plenty of hiding places and sight barriers such as live rock, real or artificial branching corals, and marine plants. It should be well planted and have lots of convenient hitching posts.

There have been a few other threads on the Ocean Rider Club discussion board at 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: Guidance on Keeping Seahorses:,com_simpleboard/Itemid,144/func,view/id,639/catid,2/

Re: New to seahorses and I have lots of questions!,com_simpleboard/Itemid,144/func,view/id,152/catid,2/

Re: Tank set-up advice,com_simpleboard/Itemid,144/func,view/id,715/catid,2/

Please let us know if you have any other questions that haven’t been covered in those previous discussions, Saoirse!

Best of luck with your ongoing seahorse research, Saoirse! Keeping reading!

Happy Trails!
Pete Giwojna

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