We need help

Dear hobbyist:

I’m sorry to hear about the difficulties you have been having with your new 10-gallon aquarium. The lack of stability and poor water quality indicate that the biological filtration in the tank is simply being overwhelmed at this point and cannot keep up with the wastes produced by the seahorses, which are messy feeders. This problem is being exacerbated by the fact that your sponges have died and are further degrading your water quality.

The first thing you need to do is to very carefully remove the sponges from the aquarium and then perform a major water change immediately. Be prepared to replace all 10 gallons of water after you extricate the sponges.

The reason you must proceed with great caution removing the sponges is because they may contain toxic substances within their fibrous bodies that could be released into the aquarium if the sponges break up or disintegrate while you are handling them. So take great care to remove the sponges complete and intact, if possible.

As soon as the sponges have been removed, replaced as much of the water in your aquarium with freshly mixed saltwater that you have preadjusted to the same temperature, pH, and specific gravity as the aquarium, and add some high-quality activated carbon to the filter on the aquarium. This will prevent any toxins that may have been leached into the water from the moribund sponges from causing harm. Filtration with activated carbon will effectively remove most organic toxins and will be very helpful in this case. Polyfilter pads may also useful in such a situation.

I would carefully remove and discard the sponges, add some heavy activated carbon filtration to your aquarium, and perform a series of water changes. Replace the activated carbon with fresh carbon after several days to remove the toxins and pollutants the old carbon has absorbed, and you should notice an improvement in your water quality.

Do not attempt to replace the dead sponges with new colorful sponges. It is going to be very difficult to keep sponges alive in a 10-gallon aquarium and I would abandon that project, which is very likely doomed to failure under the circumstances. Live sponges are best reserved for well-established reef systems.

Yes, if your seahorse tank is being overrun with anemones you definitely need to remove them. Since they have been proliferating so rapidly, it’s almost certain that they are Aiptasia rock anemones, in which case you cannot simply uproot the anemones and physically remove them from the tank. These particular anemones can reproduce by budding or fragmentation, and attempts to detach them from the substrate will often leave portions of the disc behind which can develop into new anemones.

A few isolated Aiptasia rock anemones won’t pose a serious threat to any of the larger seahorses such as Mustangs and Sunbursts (Hippocampus erectus) since the ponies will be careful to avoid them. However, as you have discovered, Aiptasia rock anemones can rapidly increase in number and become a threat to seahorses when they are so numerous it is difficult for the seahorses to avoid coming in contact with them. It sounds like that’s the situation you are now dealing with since the anemones are getting out of control in your small 10-gallon tank. The danger is not that the Aiptasia will capture and consume a small seahorse, but rather that their stinging cells or nematocysts can penetrate the integument of the seahorse and leave it vulnerable to secondary infections. For this reason, I would strongly suggest that you take measures to deforest the orchards of Aiptasia that have sprung up on your live rock.

Aiptasia rock anemones can easily be killed by injecting them with a number of solutions — Kalkwasser, boiling water, lemon juice, a number of commercial products (e.g., Joe’s Juice) — and in a severe case like yours, I suggest using a combination of such injections and biological control to eradicate them.

Peppermint Shrimp (Lysmata wurdemanni) will do a fine job of controlling Aiptasia rock anemones and they do great with seahorses. They are popular additions to a seahorse tank because hobbyists like to use them to augment their cleanup crews and add a splash of color and activity to their tanks. Aside from their utility as attractive scavengers, they often perform a useful service by grooming the seahorses, which is fascinating to watch, and regularly reproduce, releasing swarms of nauplii many seahorses love to eat. Peppermint Shrimp are especially popular because they are natural predators of Aiptasia rock anemones and do a wonderful job of eradicating these pests from the aquarium.

One rule to keep in mind when buying your Peppermints is 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. Add a few good-sized peppermint shrimp to the seahorse enclosure and they will happily clean up all of the smaller Aiptasia rock anemones.

If you pitch in by periodically injecting the largest Aiptasia, you will soon whittle down that forest of rock anemones. As the number of Aiptasia are reduced, they will become easier and easier to eliminate. There will be fewer of the large anemones for you to inject and the peppermint shrimp will eventually work their way through all of the smaller ones.

Eliminating the dead sponges and Aiptasia rock anemones will help you start to get things back on track, but you’re also going to need to be careful to feed your seahorses properly in a small tank like yours with no margin for error. This means target feeding your seahorses or training them to eat from a feeding station, as explained below:

Feeding Seahorses

When keeping seahorses in an appropriately elaborate environment, it is imperative that you feed them properly! Domesticated 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 reef or 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

Personally, 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 are 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. 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 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 (Giwojna, unpublished).

In short, feeding your seahorses properly and removing the dead sponges will help your tank to stabilize and improve the water quality, but I really think that you are fighting a losing battle attempting to keep a pair of large seahorses like Sunbursts in an aquarium that is so small. For one thing, they will not be able to mate successfully in a 10-gallon aquarium, and the lack of water depth in such a shallow tank will leave them susceptible to problems with gas bubble syndrome, a potentially fatal condition. And the water quality can go downhill so quickly in such a small volume of water that you will find it very difficult to maintain the water chemistry and aquarium parameters where you want them.

The smallest aquarium I would recommend for a pair of Mustangs or Sunbursts (H. erectus) would be a 20-gallon Extra-High All Glass Aquarium and the 30-gallon Extra-High would be much preferable. In general, if you’re new to seahorses, you will be better off starting out 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 best 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 syndrome.

So for best results you may want to consider upgrading your seahorse tank to a larger unit. Let me know if that is something you are willing to consider and I would be happy to explain the best way to go about it. A 20- or 30-gallon Extra-High All Glass Aquarium can be set up quite economically and would make a much better home for your pair of Sunbursts.

If you do upgrade your seahorse tank, then I would suggest converting your 10-gallon setup to an invertebrate tank instead. Choose out one or two pieces of colorful live rock with a good growth of coraline algae to give the 10 gallon better stability and then add some feather dusters or tubeworms, a few small hermit crabs and a small starfish or two (once the tank has stabilized), an interesting arrow crab (Stenorhynchus seticornis) and/or a decorator crab, and some decorative shrimp (perhaps a pair of coral banded shrimp, Stenopus hispidus, or Scarlet cleaner shrimp, Lysmata amboinensis). You’ll want to add some assorted snails as well to control nuisance algae and add a little more interest to the tank.

Your Sunbursts will be much happier and healthier in a larger, taller aquarium, and an interesting selection of invertebrates will be far more trouble free in your 10-gallon tank. You could also add a couple of small gobies (e.g., any goby, a clown goby, or a red head goby) to the 10-gallon invertebrate setup.

Best of luck removing a dead sponges and rock anemones and stabilizing your 10-gallon aquarium!

Respectfully,
Pete Giwojna

Dear hobbyist:

I think it’s an excellent idea for you to upgrade your seahorse setup and I would be happy to suggest a few options for you. For example, some hobbyists prefer to purchase a complete aquarium system that has been designed specifically for seahorses. That way they get everything they need in terms of filtration in one package and there is nothing more to install. In that case, the seahorse aquarium packages we discussed earlier on this forum may be worth considering:

For starters, it can recommend either the 45-gallon rectangular seahorse tank or the 35-gallon hexagonal seahorse tank available from MyFishTank.com at the following URL:

http://www.myfishtank.com/

They are beautifully designed aquariums that have the height (24 inches) and many of the features that are so desirable for a seahorse system. For example, they include a built-in a 3-in-1 filtration system that includes a wet/dry trickle filter that accommodates biological, chemical and mechanical filtration media, as well as built-in aquarium heater and an optional Clear-for-Life™ Venturi protein skimmer, all neatly contained and hidden behind a narrow false back. That’s an excellent filtration system for a seahorse setup!

As far as biofiltration goes, wet/dry trickle filters are probably the most desirable units for the seahorse keeper after live rock filtration. 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 very nice margin for error for beginners. In addition, they have compartments built right in to accommodate a protein skimmer and chemical/mechanical filtration.

Best of all, the whole filtration system is built right into the aquarium as an integral part of the whole. It requires no drilling or plumbing or modifications in order to get it up and running. There’s nothing to install and the maintenance consists primarily of rinsing and/or replacing the prefilter regularly and replacing the chemical filtration media 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.

As far as lighting goes, I understand these seahorse tanks are equipped with a fluorescent light fixture and a black ABS light hood. That’s perfectly adequate for a seahorse setup and I foresee no problems there at all.

The only complaint I have heard regarding these particular tanks is that it can sometimes be difficult to access and service the equipment behind a false back during routine maintenance, but having all of the equipment contained safely behind a false back is the safest arrangement for seahorses and gives the aquarium that polished "finished" or "prebuilt" appearance that many aquarists prefer. They are handsome aquarium systems in their own right as well as superior seahorse setups.

Either the rectangular seahorse tank or the hexagonal seahorse tank they offer would make a fine system for keeping a pair of Mustangs and a pair of Sunbursts. But the drawback for these complete aquarium packages is that they can be quite costly.

If your aquarium budget for this upgrade is tight and you are looking for a more economical set up for keeping a single pair of Sunbursts, perhaps the most basic aquarium system I could suggest would be to obtain a 20 gallon Extra-High All-Glass Aquarium (20"L x 10"W x 24"H), equip it with a simple, standard, off-the-shelf glass cover and an off-the-shelf strip reflector with a florescent bulb, and then fit it with a full set of undergravel filters that completely cover the bottom of the aquarium, as described below.

The filtration system for the tank could thus be as basic as a set of well-maintained undergravels (preferably the new reverse flow designs) that covers the bottom of the tank completely. I know undergravel filters are considered old-fashioned technology nowadays, but they are inexpensive, utterly reliable and foolproof (no moving parts), easy to install, require no modification whatsoever, and work extremely well for seahorses within their limitations. An inexpensive diaphragm air pump will operate the filter and provide all the aeration you need, or you can upgrade to powerheads for greater efficiency and extra water movement.

For the substrate with your undergravel filters, use a coarse bed of good calcareous aquarium gravel such as dolomite, aragonite, or crushed oyster shell 2-3 inches deep, since the buffering ability of such substrates will help maintain good pH.

It is a good idea to supplement the undergravels with an inexpensive hang-on-back filter or canister to provide better circulation and accommodate chemical filtration media. This is a very simple, inexpensive aquarium that’s extremely easy and economical to set up and operate, yet it can be very successful if used within its limitations. For instance, undergravel filters are notorious nitrate factories and the hobbyist must take measures to compensate for this fact. This simple system relies totally on water changes to control nitrates. There is no live rock or live sand bed to provide denitrification, no algal filter or denitrator in a sump, and no protein skimmer to remove organics before they enter the nitrogen cycle. This limits the carrying capacity of the tank and makes an accelerated maintenance schedule and more frequent water changes an absolute necessity. For this reason, reverse flow undergravels often work best with seahorses; they help prevent detritus from accumulating in the gravel bed.

I recommend weekly water changes of a least 25% for such a system. Use a gravel washer to clean a different portion of the gravel bed (no more than 25%) each week and keep the tank under stocked. If you are diligent about aquarium maintenance, perform water changes religiously, and limit yourself to fewer seahorses that you feed carefully, you will find that a simple system featuring undergravel filters can be very successful. But if you are negligent with regard to maintenance, skimp on water changes, or tend to overcrowd or overfeed your tanks, this system will be very unforgiving.

As we have already discussed, it’s generally best to start out with the largest tank you can reasonably afford and maintain, the taller the better, in order to provide yourself with a comfortable margin for error if these are your first seahorses. The 20-gallon Extra-High All Glass Aquarium we have already discussed is the smallest tank I would consider using for it pair of Sunbursts, but if you can afford to spend just a little more than I would suggest the 30 gallon Extra-High All-Glass Aquarium (24"L x 12"W x 24"H), which won’t cost much more but which will provide you with a bigger margin for error. Any local fish store can order one for you and it’s an economical tank with excellent height for seahorses at 24-inches tall. You can then equip it the same as the 20-gallon tank, using a simple, standard, off-the-shelf glass cover and an ordinary off-the-shelf strip reflector with a daylight florescent bulb, and that can form the basis of an inexpensive yet solid seahorse setup.

If you can afford to upgrade the filtration system a notch above undergravels, many seahorse keepers prefer well-cured, "debugged" live rock to provide all or most of the biofiltration for their aquariums. A simple external hang-on-the-back filter or an efficient canister filter instead that is rated for an aquarium of the size you have chosen could then be added on to provide water circulation, surface agitation for good oxygenation, and the means for providing mechanical and chemical filtration.

Of coarse, no matter what size aquarium you decide on for your upgrade, you will first have to cycle the tank before it will be able to support seahorses or any other life. Here are some suggestions to keep in mind when cycling your new setup:

Cycling the Aquarium

Once you’ve rounded up the aquarium, equipment, and accessories you need, your next task is to prepare the tank for cycling. Until it has cycled, your aquarium will be unable to support life. Cycling simply means to build up a healthy population of beneficial bacteria in your tank that can carry out the nitrogen cycle and breakdown your fishes’ waste products.

The amount of nitrates that accumulate in your aquarium are related to how much nitrification and denitrification your system provides. Nitrification is the process by which aerobic (oxygen loving) nitrifying bacteria break down toxic ammonia to relative harmless nitrate in a series of steps. Nitrification thus ultimately causes nitrate to build up in an aquarium. Denitrification is the process by which anaerobic (oxygen hating) denitrifying bacteria then convert nitrate into completely harmless nitrogen (N2), which eventually leaves the aquarium. Denitrification thus removes nitrate from your system. This entire process is known as the nitrogen cycle.

As I mentioned, cycling your aquarium simply means to build up a large enough population of beneficial bacteria in your tank that can carry out the nitrogen cycle and breakdown your fishes’ waste products. Ammonia (NH3), nitrite (NO2), and nitrate (NO3) are all nitrogenous (nitrogen containing) wastes. All living aquarium animals whether they be fish or invertebrates excrete these wastes, and they are also produced by the decay of protein-containing organic matter (uneaten food, detritus, dead fish or inverts, etc.). The nitrogen cycle breaks down these wastes in a series of steps into nitrogen gas (N2) which leaves the aquarium as bubbles.

The nitrogen cycle begins with ammonia, which is highly poisonous. In the first step of the cycle, Nitrosomonas bacteria reduce ammonia to nitrite, which is also very toxic. In the second step of the nitrogen cycle, Nitrobacter bacteria convert the nitrite to nitrate, which is relatively harmless but becomes harmful when it accumulates in high enough levels. In the third and final step of the cycle, denitrifying bacteria then convert the nitrate into completely harmless N2, which of course bubbles out of the tank as nitrogen gas. In this way, thanks to the nitrogen cycle, dangerous wastes are converted into progressively less harmful compounds and finally removed from the aquarium altogether.

When we set up a new aquarium, and wait for it to cycle, we are simply allowing a big enough population of these different types of bacteria to build up in the biofilter to break down all of the wastes that will be produced when the aquarium is stocked. If we don’t wait long enough for the cycle to complete itself and the biofiltration to become fully established, or hastily add too many specimens to a new aquarium too soon, they will die from ammonia poisoning or nitrite toxicity. This is such a common mistake among us impatient aquarists, that when fish get sick and/or die from ammonia/ntrite poisoning, it is commonly called the "new tank syndrome."

When your aquarium has completely cycled, the ammonia levels will stay at zero because, now that your biofilter is fully established, there is a large enough population of aerobic (oxygen loving) nitrifying Nitrosomonas bacteria to reduce all of the ammonia to nitrite as fast as the ammonia is being produced. The nitrite levels will likewise stay at zero because there is also a large enough population of aerobic (oxygen loving) nitrifying Nitrobacter bacteria to convert all of the nitrite to nitrate as fast as the nitrite is being produced.

The nitrate levels ordinarily continue to build up, however, because there are simply not enough anaerobic (oxygen hating) denitrifying bacteria to convert all of the nitrate that’s being produced into nitrogen gas (N2). Since nitrates are being produced faster than they can be transformed to nitrogen gas, the excess nitrates accumulate steadily in your aquarium. That’s perfectly normal, since the denitrifying bacteria that carry out that final step, the conversion of nitrate (NO3) to nitrogen (N2), are anaerobes that can only exist in the absence of oxygen. For our aquariums to support life, and for the fish and invertebrates to breathe and survive, our tanks must be well aerated and well circulated so that there’s plenty of dissolved oxygen in the water at all times. That means there are normally very few areas in our aquariums where anaerobic denitrifying bacteria can survive, limiting their population accordingly (which is generally good, since some anaerobes produce deadly hydrogen sulfide gas during the decay of organic matter and would poison our tanks if allowed to proliferate).

Consequently, most aquariums lack a sufficient population of anaerobic denitrifying bacteria to complete the nitrogen cycle and convert nitrate to nitrogen as fast as the nitrates are being produced. The only way to keep the nitrates from building up to harmful levels in such setups is with regular water changes and by harvesting Caulerpa or other macroalgae periodically after it has utilized nitrates for growth. Overcrowding, overfeeding, or under filtration exacerbate the problem by resulting in more nitrates being produced and more frequent water changes being required to control the nitrate levels.

Live rock helps because the oxygen-poor interior of the rock allows anaerobic denitrifying bacteria to grow and break down nitrates. A deep live sand bed (DLS also helps because anaerobic denitrifying bacteria can flourish and break down nitrates at a certain depth below the sand where oxygenated water no longer penetrates, but a DLSB can sometimes be difficult to set up and manage properly if you’re inexperienced with live sand. Both live rock and deep live sand beds give aquaria denitrification ability — the ability to complete the cycle and convert nitrate to harmless nitrogen. Ordinarily, about 1-2 pounds of live rock per gallon is recommended – that amount of LR will provide your aquarium with all of the biofiltration you need, as well as significant denitrification ability. You will keep nitrates at harmless levels by performing regular water changes, harvesting Caulerpa macroalgae periodically, and good aquarium management.

Prepare your aquarium for cycling by setting your system up with just freshwater at first, attaching the equipment and apparatus (filter, aeration, circulation, heater, skimmer, lighting, accessories) and testing it all for a day or so to make sure you have everything in place, and that it works. Once assured that everything’s operating properly and there are no leaks, go ahead and add the substrate, salt mix, and aquarium décor, and leave everything running for a good week, allowing the various components and water to "settle in" before adding your microbes and "seeding" the tank with beneficial bacteria that will eventually establish your biofilter.

If you are using live rock, it contains all the bacteria needed to seed the tank, so all you have to do is position the live rock in attractive arrangements and wait for the population of nitrifying and denitrifying bacteria to build up and stabilize.

If you are not using live rock, there are a number of different ways to seed the tank with bacteria and feed it with ammonia so cycling can proceed. Two popular methods are the fishless cycle, which I recommend, and the use of hardy, inexpensive (i.e., expendable) fish to produce ammonia and cycle the aquarium.

Often used for this method are marine damselfish or mollies, which can easily be converted to saltwater. Both are very hardy and generally survive the cycling process, but I find this method to be needlessly hard on the fish and exposing them to the toxic ammonia and nitrite produced during cycling certainly causes them stress. Damselfish are far too aggressive and territorial to leave in the aquarium afterwards as tankmates for seahorses, and it can be devilishly difficult trying to capture them in a tank with lots of live rock so they can be removed once the tank has been cycling. Mollies are a possibility, but they really look out of place in a saltwater setup. Even if the fish survive the cycling process, the stress from the build up of ammonia and nitrite may well result in an outbreak of marine ich (Cryptocaryon irritans) or some other affliction, and you may find yourself attempting to eradicate a stubborn pathogen from your tank before it’s ready for the seahorses.

So all things considered, I suggest you try cycling your tank without fish. It’s really very easy. To use the fishless cycle, you need to add something else that will increase the ammonia level so the nitrifying bacteria can build up. I like to use a piece of cocktail shrimp (regular uncooked eating shrimp from the grocery store) and leave this in the tank to decay during the whole cycle. The decaying shrimp produces plenty of ammonia to kick-start the cycling process.

After about 3 days after you add the shrimp, you will notice a spike in ammonia levels until the Nitrosomonas bacteria build up enough to break down the ammonia. When that happens, you will notice the ammonia levels rapidly dropping. (If for some reason your ammonia does not hit the top of the charts initially, you may want to add another piece of shrimp.)

The byproduct of ammonia is nitrite, and during this stage of the cycling process, as the ammonia falls, you will have a corresponding increase in nitrites until the population of Nitrobacter bacteria builds up. Nitrite levels will then fall as the Nitrobacter convert the nitrite to nitrate.

It is important to use your test kits every day or two when cycling your tank to monitor the progress of the process. As described above, at first you will see a rapid rise in ammonia levels with no detectable nitrite or nitrate. Then, as Nitrosomonas bacteria begin converting ammonia to nitrite, the ammonia levels will fall and nitrite readings will steadily rise. Nitrite levels will peak as the ammonia drops to zero. Next, Nitrobacter will begin converting the nitrite to nitrate, and your nitrite readings will fall as the level of nitrate rises. Finally, after the nitrites also read zero, you are ready to stock your tank. At this point, your ammonia and nitrite levels should both be zero, nitrates will be building up, and algae will usually begin to grow. This will tell you that your biofilter is active and functioning properly, and that you can now safely begin stocking the tank. It generally takes about 3-6 weeks to cycle a tank this way from scratch.

Best of luck upgrading to a more spacious aquarium for your Sunbursts!

Respectfully,
Pete Giwojna