Synthetic Coral

Dear Kris:

Yikes! What an awful shame — that’s the worst seahorse-related news I’ve heard in a long, long time! A catastrophic tank wipeout is always devastating, but under the circumstances you describe, I can only imagine how disheartening and demoralizing the experience must be! All my condolences on your tragic loss, Kris!

For whatever it’s worth, I would certainly be happy to share my thoughts on the matter with you, Kris, but I don’t know how helpful I can be. This case is as baffling as any I’ve seen.

First of all, I can say that I don’t believe that any sort of an illness or disease process was involved. I know of no pathogens or parasites, or any other disease processes for that matter, that are so contagious and virulent that they could wipe out a whole herd of healthy seahorses literally overnight without any premonitory signs or symptoms. So I think we can rule out any kind of ailment or affliction in this case, Kris.

In my experience, when a tank full of healthy seahorses is wiped out overnight after they had perfectly fine and asymptomatic the night before, it is almost always due to an environmental problem of some sort, most often either poisoning or hypoxia. With that in mind, let’s review some of the common environmental factors that can be harmful to seahorses, as explained in the following excerpt from my new book (Complete Guide to the Greater Seahorses in the Aquarium, TFH Publications, unpublished):

<open quote>
Environmental Diseases Associated with Water Quality

Ammonia poisoning and nitrite toxicity are the most common of these problems (Indiviglio, 2002). Ammonia is highly toxic to fish and invertebrates in even small amounts (> 0.01 mg/L or ppm). Nitrite is slightly less poisonous to fishes, but deadly to some invertebrates at very small concentrations (0.01 mg/L or ppm). To be safe, ammonia and nitrite levels must be kept at zero at all times.

Dangerous levels of ammonia and nitrite can build up in the aquarium for many reasons. Failure to cycle the tank properly and establish the biofilter is a common beginner’s mistake, as is adding too many specimens too soon before the biofilter can adjust to the heavier bioload (i.e., new tank syndrome). Impairment of the biofiltration can also cause ammonia and nitrites to reach dangerous levels. This can result from medicating the main tank, a lack of oxygen for the beneficial aerobic bacteria due to a pump failure or power outage, disrupting the live sand bed too deeply when cleaning the substrate, and so on. The undetected death of tankmate such as a starfish or large snail can lead to harmful ammonia and/or nitrite spikes after it begins to decompose, as can overcrowding and overfeeding. Ammonia spikes are a common problem following a heavy feeding.

Seahorses suffering from ammonia and/or nitrite poisoning will struggle to breathe. The symptoms to look are a loss of equilibrium, hyperexcitability, increased respiration and oxygen uptake, and increased heart rate. At extreme ammonia or nitrite levels, fish may experience convulsions, coma, and death. Seahorses exposed to less extreme ammonia levels will struggle to breathe. They will be lethargic and exhibit rapid respiration. They may appear disoriented, periodically detaching from their hitching posts only to sink to the bottom. They will be lethargic and exhibit rapid respiration. Test kits can often confirm your diagnosis by revealing unacceptable levels of ammonia and/or nitrite in the water, but transitory ammonia splikes (following a heavy feeding, for example) may not be detected by testing the water after the fact.

The appropriate treatment is to immediately transfer the seahorses to clean saltwater in a hospital tank and add methylene blue, which aids oxygen transport in the blood. Methylene blue will help seahorses with ammonia poisoning to breathe, and can actually reverse the effects of nitrite toxicity. While the seahorses are undergoing treatment, partial water changes will reduce the levels of ammonia/nitrite in the main tank. The cause of the problem must then be determined or corrected. This can be as quick and easy as finding and removing a dead specimen or as difficult and time consuming as recycling the entire tank.

Heavy metal poisoning is another environmental disease hobbyists must sometimes contend with. Even tiny concentrations of heavy metals are deadly to marine fish and invertebrates. This used to be a common cause for concern among marine aquarists when steel-framed aquariums were commonplace, but the advent of all-glass tanks and acrylic aquaria have greatly reduced such problems.

The chief offender nowadays is copper, which usually becomes a problem when the hobbyist overdoses the tank with a copper-based medication (Indiviglio, 2002). Other times copper enters the aquarium in tap water used for water changes or topping off the tank. The copper is leached into the tap water from copper pipes and plumbing (Indiviglio, 2002).

Other heavy metals (iron, lead, and aluminum) sometimes also present a problem when they are accidentally introduced to the aquarium in rocks, gravel, ornaments or decorations. Some of rocks and gravel sold (e.g., red flint) for freshwater use are unsafe in marine tanks because of a high metal content. The same is true for many aquarium ornaments and decorations (Giwojna, 1990). Be especially wary when purchasing artificial plastic plants for the aquarium. Stick with calcareous rocks and gravel and make certain any ornaments or plastic plants you consider are designed for use in marine aquariums and certified to be safe.

Even the popular sponge or foam filters are often a hazard. Many of them contain metal weights as ballast to hold them on the bottom, which is fine in freshwater but can be deadly in a saltwater setup when the metal slugs corrode and leach heavy metal ions into the water.

Seahorses suffering from heavy metal poisoning will act as if they are falling-down drunk. They will be listless and loggy, and if they attempt to move, they will be disoriented, bump blindly into things, and have great difficulty maintaining their normal equilibrium and balance (Giwojna, 1990). And they will be breathing hard and fast.

Treatment is as for ammonia/nitrite poisoning — get them into clean saltwater ASAP, identify the source of contamination and eliminate it, and change out the water in the main tank. Polyfilter pads pull out copper and many heavy metals and may be especially useful in such a situation.

Contamination of the aquarium water with household chemicals is another common problem for the hobbyist (Indiviglio, 2002). Avoid using anything that gives off strong fumes anywhere near your aquarium! This includes bleach, paint, lacquer, varnish, paint thinner, turpentine, insect sprays, bug bombs, pesticides, hairy spray, cigarette smoke, and household cleaners of all kinds (Giwojna, 1990). Even if the aquarium is tightly covered or sealed with plastic, airborne contaminants from fumes and aerosols will still be pumped into the aquarium from the air pumps (Indiviglio, 2002). To prevent this from happening when you must use such products near an aquarium that cannot be moved, disconnect the air pumps first and work only in well-ventilated area. Use submersible powerheads to maintain circulation in the covered aquarium, work fast, and air out the room thoroughly before you reconnect the air supply.

Medicating the aquarium is the worst possible thing you can do when seahorses are suffering from diseases related to water quality or environmental problems such as the toxic conditions described above (Giwojna, 1990). Afflictions such as these are not caused by parasites or pathogens, so medicating the tank not only fails to address the problem, it actually makes matters worse (Giwojna, 1990). Chemotherapeutic agents can be harsh on the seahorses, especially when they are already weakened due to poor water quality or actual poisoning. Worse yet, they are often hard on the biofilter as well and apt to further degrade water quality by killing off beneficial Nitrobacter and Nitrosomonas bacteria.

Stray voltage is another common cause of chronic stress for seahorses and other aquarium inhabitants, as well as a much more prevalent problem than most hobbyists suspect. Installing a grounding probe in the tank easily prevents it, and every seahorse setup should be equipped with one. A titanium grounding probe is an inexpensive investment that can safeguard the health of your seahorses.

Hypoxia due to low oxygen levels or high carbonic dioxide levels is another environmental condition that has been known to kill seahorses suddenly and without warning. This often tends to happen overnight when CO2 naturally rise as O2 levels are dropping due to the reversal of photosynthesis.

As you know, while they are photosynthesizing during the day, zoanthellae and algae consume CO2 and produce O2, but at night, in the absence of light, this process is reversed and the photosynthetic organisms consume O2 and give off CO2 instead. Seahorse setups in general are susceptible to such problems because hobbyists are so conscious of their seahorses’ limited swimming ability that they tend to leave their aquariums undercirculated. Poor circulation and inadequate surface agitation can lead to inefficient oxygenation and insufficient offgassing of carbon dioxide.

Seahorses are more vulnerable to low O2/high CO2 levels than most fishes because of their primitive gills. Unlike most teleost (bony) fishes, which have their gills arranged in sheaves like the pages of a book, seahorses have rudimentary gill arches with small powder-puff type gill filaments. Seahorses are said to have "tufted" gills because they appear to be hemispherical clumps of tissue on stems. Their unique, lobed gill filaments (lophobranchs) are arranged in grape-like clusters and have fewer lamellae than other teleost fishes. Because of the difference in the structure and efficiency of their gills, seahorse are unsually vulnernable to hypoxia when CO2 levels are high and/or O2 levels are low.

Most deaths due to hypoxia occur when the water pump or filter fails during the night, or there is a power outage overnight when the aquarist is unaware, cutting off the filtration, water circulation, and aeration of the aquarium with devastating results. <End quote>

That’s the rundown on the common environmental problems that can prove fatal to seahorses, Kris. Whatever wiped out your herd is most likely something on the list above, and after looking over this list of potential environmental problems, it’s apparent that most of them can be ruled out immediately in your case. Ammonia poisoning and/or nitrite toxicity is most unlikely since your aquarium is well-established and your seahorses have been healthy for a considerable period of time at their current stocking density and your usual feeding regimen. So unless there was a large specimens whose death went undetected long enough for it to begin to decay, we can probably cross off ammonia/nitrite poisoning from the list of suspects. I think we can rule out hypoxia and asphyxiation as well, since there was no catastrophic equipment failure or power outage during the night that knocked out your filtration and aeration. We can also disregard stray voltage, since that’s a chronic stressor that debilitates fish gradually rather than killing them suddenly.

Only you can determine if heavy metal poisoning or accidental contamination of the water with household chemicals could have been involved, Kris, but the diligent aquarist is always very careful to avoid situations that could lead to such problems, and I believe you are one such conscientious aquarist.

So I think your suspicions are probably correct. My best guess is that the new piece of artificial coral leached something into the water that was harmful to the seahorses. That used to be a common problem in the early days of the marine aquarium hobby, when most all of the aquarium decorations were intended for use in freshwater and therefore were not always safe to use in saltwater.

In those days, it was SOP to soak artificial plants, fake corals, and the like in a concentrated brine solution that was changed periodically for several days or weeks as a precaution before you considered adding it to your saltwater aquarium. But nowadays there are many lines of artificial corals and decorations that are designed specifically for use in marine aquaria, and that’s no longer the case. Such decorations are becoming so realistic and lifelike that it is difficult to tell the faux corals and gorgonians from the real thing. As a rule, such precautions are no longer necessary when you purchase artificial corals that are certified to be safe for marine aquariums.

Did the large piece of red coral include instructions for cleaning it and maintaining it, Kris? Nowadays, most artificial corals come with some sort of directions in that regard so that you don’t damage them when cleaning them and removing algae, etc., and these instructions will usually include some sort of guarantee or certification that they are safe for use in saltwater aquarium, as well as pointing out specifically if you need to do anything by way of preparation such as soaking them in water or rinsing them before they go into the aquarium.

I would contact the manufacturer of the coral and explain what happened. Perhaps the manufacturer can offer some additional insight into what may have happened. The timing of the wipeout is extremely suspicious, which makes me think it is more than a coincidence that the seahorses were all dead or dying within a matter of hours after you added the new piece of artificial coral.

I cannot imagine what else could have caused your tank to crash, but if it was due to the artificial coral, that is truly rare bad luck. I have used a wide variety of artificial corals and plants in my seahorse tanks over the years and never had any problems.

Best of luck unraveling this mystery and setting things straight again, Kris. Here’s hoping the sole survivor hangs in there and makes a complete recovery.

Respectfully,
Pete Giwojna