How to convert 55gal for Seahorses?

Dear Cajun:

I’m very sorry to hear about the accident that wiped out your tank. It sounds like the decay of all the dried shrimp that got dumped into the aquarium at once caused a massive ammonia spike, or perhaps a deadly rise in both the ammonia and nitrite levels.

If that is indeed the case, then a thorough aquarium cleaning followed by a series of water changes to restore optimal water quality may be all you need to do in order to make your 55-gallon tank habitable again.

But if the fish and invertebrates were not killed off directly by the rising ammonia and/or nitrite levels following the spill — if the increase in ammonia/nitrite and the degraded water quality merely stressed the fish and left them vulnerable to other disease processes (bacterial or fungal infections, or perhaps parasite problems of some sort), then you may be better off depopulating the tank, tearing down everything, and starting over from scratch. That may be the only way to a sure that a lingering reservoir of disease does not remain in the aquarium, which could jeopardize the next residents of the tank, if a contagious illness or infection of some sort ultimately wiped out the tank.

Can you tell me a little more about how you actually lost the fish in the aquarium, sir? Was it the environmental conditions (i.e.,/ammonia/nitrite poisoning) that overwhelmed them, or did they eventually succumb to an infection or ailment of some sort after they had been weakened by the high ammonia/nitrite levels?

Otherwise, the equipment you have and the aquarium themselves are fine and can form the basis of an excellent system for keeping seahorses. The live rock is great and you have enough to provide both efficient nitrification and considerable denitrification for your aquarium. With the live rock acting as your primary biofilter, the canister filter is all you need to provide additional water movement and a source of mechanical and chemical filtration. The Cascade 700 unit is only rated for 185 gallons per hour, so it should not be too overpowering for the seahorses at all. (If possible, use the spray bar return for the Cascade 700 and position it just above the water level so that it provides good surface agitation to promote better oxygenation and efficient gas exchange at the air/water interface.) The Reef Sun 50/50 fluorescent light fixture is good, and a trichromatic daylight phosphor bulb plus an actinic bulb is a good combination.

However, the Maxijet 1200 will generate currents that are too strong and turbulence that is too powerful for seahorses in a 55-gallon aquarium. The filtration in the seahorse tank should turn over the entire volume of the tank a minimum of five times every hour, but not much more than that, so I would replace the Maxijet 1200 with another unit — nothing more powerful than a Maxijet 400 powerhead for this tank at the most. With a smaller Maxijet to provide good circulation throughout the tank and a protein skimmer to supplement the filtration and help assure optimal water quality, you should be all set.

My only other concern with the aquarium as you have it set up now, Cajun, is the very deep sand bed. I am actually a big proponent of a Deep Live Sand Bed (DLSB) 4-6 inches in depth for seahorses, but I strongly feel they are best confined to the sump or refugium rather than established in the main tank. With an 8-inch sand bed, you are reducing the water depth in the main tank to a good 7 inches less than what it would be if you had just a shallow layer of live sand. That’s unfortunate because the depth of the sand bed reduces the vertical swimming space in the main tank and shortens the water column, which therefore provides less protection to the seahorses from depth-related problems such as certain forms of gas bubble syndrome (GBS). With the sand bed in place, the aquarium will be too shallow for the larger species of seahorses to mate comfortably and may leave them susceptible to problems with GBS. Also, seahorses are messy eaters and have a rapid defecation rate when they are well fed, which leaves a lot of organic waste for a DLSB to process.

To be successful, a DLSB needs to be installed properly and maintained diligently. It needs to be layered properly with sand and gravel of the correct grain size and texture and must be equipped with a full complement of sand sifters. This complicates matters for the seahorse keeper since some of the best sand sifters are not fully compatible with seahorses. For this reason, a DLSB for a seahorse tank will produce the best results if it is located in the sump or refugium.

So one thing you may want to consider is to install a sump on your 55-gallon aquarium and then relocate the DLSB to the sump instead of having it in the main tank. There are many advantages to adding a sump 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 (DLSB) 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 partitioning the sump to divided into two or more separate chambers. This can be accomplished by installing perforated tank dividers across the width of the sump, thereby separating it into two or more isolated compartments. One of the compartments can accommodate all of your equipment (in-sump skimmer, return pump, heaters, titanium grounding probe, UV sterilizer, etc.) while another of the compartments can be used to establish a deep live sand bed (DLSB) with plenty of Caulerpa or Chaetomorpha turf algae. The DLSB/macroalgae side serves as a refugium and will soon become populated with countless critters (copepods, Gammarus and other amphipods, larval crustaceans, etc.). With the Caulerpa and/or Chaetomorpha 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 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. (Other macroalgae require a period of darkness in order to thrive, but if you will be using Caulerpa, it can even be illuminated 24 hours a day around the clock in order to accomplish the same thing.) 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.

For additional information on setting up and maintaining a DLSB, check out the following FAQs site by the wetwebmedia guys. Skim through it carefully and it should give you lots of good ideas regarding how to keep your DLSB functioning properly:

Click here: DSBFAQs
<http://wetwebmedia.com/dsbfaqs.htm&gt;

Mustangs and Sunbursts (Hippocampus erectus) are excellent choices for anyone who is new to seahorse keeping, so you’re on the right track regarding the type of seahorses that are well suited for a tank like yours. You will also need to add an assortment of convenient hitching posts to your aquarium for the benefit of the seahorses. If you contact me off list ([email protected]), I will be happy to recommend some good hitching posts for you and provide you with a lot of additional information on optimizing your aquarium to create ideal conditions for Mustangs and Sunbursts.

Otherwise, as long as you feed the seahorses properly, I don’t foresee any serious problems in transforming your 55-gallon tank into a suitable seahorse setup, Cajun. As you know, cultured seahorses thrive on enriched frozen Mysis as their staple, everyday diet. But the worst thing you can do when feeding the seahorses in a intricate live rock environment is to scatter a handful of frozen Mysis throughout the tank to be dispersed by the currents and hope that the hungry horses can track it all down. Inevitably some of the frozen food will be swept away and lodge in isolated nooks and crannies where the seahorses cannot get it (Giwojna, 2005). There it will begin to decompose and degrade the water quality, which is why ammonia spikes are common after a heavy feeding. Or it may be wafted out into the open again later on and eaten after it has begun to spoil. Either outcome can have dire consequences (Giwojna, 2005).

The best way to avoid such problems is to target feed your seahorses or set up a feeding station for them. See my online article in Conscientious Aquarist for a detailed discussion explaining exactly how to set up a feeding station and train your seahorses to use it:

Click here: Seahorse Feeders
http://www.wetwebmedia.com/ca/volume_2/cav2i5/seahorse_feeders/seahorse_feeders.htm

But I prefer to target feed my seahorses instead. The individual personalities of seahorses naturally extend to their feeding habits. Some are aggressive feeders that will boldly snatch food from your fingers, while some and shy and secretive, feeding only when they think they’re not being observed. Some like to slurp up Mysis while it’s swirling through the water column, and some will only take Mysis off the bottom of the tank. Some are voracious pigs that greedily scarf up everything in sight, and some are slow, deliberate feeders that painstakingly examine every morsel of Mysis before they accept or reject it. Some eat like horses and some eat like birds. So how does the seahorse keeper make sure all his charges are getting enough to eat at mealtime? How does the hobbyist keep the aggressive eaters from gobbling up all the mouth-watering Mysis before the slower feeders get their fair share? And how can you keep active fishes and inverts with seahorses without the faster fishes gobbling up all the goodies before the slowpoke seahorses can grab a mouthful (Giwojna, unpublished)?

Target feeding is the answer. Target feeding just means offering a single piece of Mysis to one particular seahorse, and then watching to see whether or not the ‘horse you targeted actually eats the shrimp. Feeding each of your seahorses in turn that way makes it easy to keep track of exactly how much each of your specimens is eating (Giwojna, unpublished).

There are many different ways to target feed seahorses, including handfeeding, which I prefer. Most methods involve using a long utensil of some sort to wave the Mysis temptingly in front of the chosen seahorse; once you’re sure this has attracted his interest, the Mysis is released so it drifts down enticingly right before the seahorse’s snout. Most of the time, the seahorse will snatch it up as it drifts by or snap it up as soon as it hits the bottom (Giwojna, unpublished).

A great number of utensils work well for target feeding. I’ve seen hobbyists use everything from chopsticks to extra long tweezers and hemostats or forceps to homemade pipettes fashioned from a length of rigid plastic tubing. As for myself, I prefer handfeeding when I target feed a particular seahorse (Giwojna, unpublished).

But no doubt the all-time favorite implement for target feeding seahorses is the old-fashioned turkey baster. The old-fashioned ones with the glass barrels work best because the seahorses can see the Mysis inside the baster all the way as it moves down the barrel and out the tip. By exerting just the right amount of pressure on the bulb, great precision is possible when target feeding with a turkey baster. By squeezing and releasing the bulb ever so slightly, a skillful target feeder can keep a piece of Mysis dancing at the very tip of the baster indefinitely, and hold the tempting morsel right in front of the seahorse’s mouth as long as necessary. Or if the seahorse rejects the Mysis the first time it drifts by, a baster makes it easy to deftly suck up the shrimp from the bottom so it can be offered to the target again. In the same way, the baster makes it a simple matter to clean any remaining leftovers after a feeding session (Giwojna, unpublished). (You’ll quickly discover the feeding tube is also indispensable for tapping away pesky fish and invertebrates that threaten to steal the tempting tidbit before an indecisive seahorse can snatch it up.)

In short, target feeding allows the hobbyist to assure that each of his seahorses gets enough to eat without overfeeding or underfeeding the tank. And it makes it possible to keep seahorses in a community tank with more active fishes that would ordinarily out-compete them for food, since the aquarist can personally deliver each mouthful to the seahorses while keeping more aggressive specimens at bay (Giwojna, unpublished).

The key to keeping active specimens like Firefish or cleaner shrimp successfully with seahorses is to feed the other fish and inverts with standard, off-the-shelf aquarium foods first, and once they’ve had their fill, then target feed the seahorses.

Best of luck converting your 55-gallon aquarium into a seahorse system, Cajun! I’m looking forward to hearing from you off list so I can make sure that we get you started off on the right foot.

Respectfully,
Pete Giwojna