Re:hazy/cloudy water quality

Dear Kay:

I’m not sure what you mean when you say the tank is a little foggy up close to the top of the water. Normally, a well-filtered marine aquarium is crystal clear from top to bottom, so I would be concerned if there is still some cloudiness near the surface of the aquarium. If it’s due to a bacterial bloom, it should eventually disappear on its own as you control the excess nutrients in the water through the changes you made when feeding the seahorses. The good circulation should help, particularly if there is adequate surface agitation.

Yes, I think it was a good idea to transfer your tiny seahorse to these smaller aquarium if he was having difficulty coping with the current in the main tank. When he grows up a little and puts on a little more size, you can return him to the main tank with the rest of the herd.

There is a good way to determine if the water flow from your filter is too strong for the seahorses or not, Kay. All you have to do is collect the outflow from your Whisper filter where it normally enters the aquarium. Collect all of the water that is throwing through the Whisper for 30 seconds, measure the volume of water that you collected, and then multiply that by 120. That will give you the actual flow rate for 60 minutes or one hour, with no guesswork involved. Then you can divide that number by the capacity of your aquarium to see how many times the tank is being turned over every hour.

For example, if the Whisper filter puts out 1-1/2 gallons of water in 30 seconds, multiply that by 120 and you see that the filter is pumping out 180 gallons per hour (1.5 x 120 = 180). Then if you divide 180 by the capacity of your hex tank, you’ll see that the whisper filter would be turning over the entire volume of your aquarium a little over five times every hour (180/35 = ~5). In this example, that would be just about the perfect amount of circulation for your seahorse tank.

You ordinarily want the filtration on a seahorse tank to be turning over the entire volume of the aquarium 3-5 times every hour. Personally, I would say that your seahorse tank is under circulated if it doesn’t turn over the entire volume of the aquarium at least five times an hour. So for your 35-gallon aquarium, you want the output from your filter/water pump to be at least 175 gallons per hour, in my estimation.

If the filtration produces turnover rates considerably in excess of five times the volume of the tank every hour, then you need to start to be concerned about generating too much water flow and too much current for the seahorses. If you have a spray bar return or waterfall return that diffuses the output from the filter, then you can achieve turnover rates of 10 times the total water volume of the aquarium every hour without producing too much turbulence and overpowering the seahorses in a tall tank. But if you don’t have a spray bar return or waterfall return that splashes the output from the filter into the aquarium and attenuates the water flow, then turning over the volume of your aquarium much more than 5 times every hour may produce currents that can overwhelm the limited swimming ability of the seahorses, so be careful about increasing the turnover rate too much.

Here’s what I normally advise hobbyists with regard to the water movement in their seahorse tanks, Kay:

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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. We often find Seahorses in flat muddy/silt areas nowhere near rocks or weed. These areas are often scoured by strong currents and the Seahorses do well in them and seem completely unperturbed by the current. In setting up a tank for them I try to remember the feeling I had in those areas and replicate them. (Garrick-Maidment, Jun. 2002)."

Kirk Strawn, who earned his Master of Science thesis studying Hippocampus zosterae in the field, echoes Neil’s thoughts on the matter:

"The aquarist is not giving his seahorses natural conditions when he keeps them in a still-water aquarium. In nature tidal currents, wind, and waves are usually mixing the well aerated surface film water with the deeper water."

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.

In short, if your filtration is not turning over the entire volume of the aquarium a MINIMUM of 5 times per hour, your seahorse setup is probably undercirculated. With a spray bar return raised above the surface of the water to diffuse the outflow, you can achieve turnover rates of several times that much without producing too much turbulence or current for seahorses. A waterfall return is another good way to diffuse the output from your filter, and also works well for seahorses. There will be an area of relatively vigorous water movement at one end of the aquarium underneath and nearby the waterfall, while the other end of the tank is a relatively low flow area.

But as with anything, too much of even a good thing can be undesirable, and too much current can overwhelm the limited swimming ability of Hippocampus. One indication that you may have too much water movement in your seahorse tank is if the seahorses are getting buffeted around by the currents, and whisked away uncontrollably when they tire of fighting the current. Or alternatively, they may stay perched in one place all the time and refuse to swim around and explore their tank for fear of getting swept away by the current if they relax their grip on their hitching posts. So you can get a pretty good gauge of how well the seahorses are able to cope with the water movement than their tank by observing how the current affects the swimming ability.

Likewise, if a mated pair of seahorses is consistently spilling eggs during the copulatory rise, that’s another pretty good indication that there may be too much turbulence or water movement in the upper reaches of their aquarium.

If the seahorses are having difficulty tracking their prey and eating because the current whisks the frozen Mysis past them too quickly to target it accurately and slurp it up, that’s another red flag. Often that situation can be corrected simply by adjusting the output from your filter to reduce the current during feeding time or turning it off altogether while a seahorses are eating.

But as long as your seahorses aren’t getting buffeted around, aren’t routinely dropping eggs during disrupted mating attempts, and aren’t having difficulty targeting their prey and eating, there’s really no such thing as too much water movement. In general, the stronger the water flow, the more important it is to keep the water currents steady and unvarying so the seahorses can establish holding areas in the sheltered spots and low-flow zones downcurrent without getting blindsided by unpredictable currents. Just make sure your seahorses are not getting trapped against overflows and be sure to screen off the intakes for any powerheads. Powerheads can be switched off at feeding time, if necessary.

In short, there is a fairly simple way to roughly determine whether or not the water movement and circulation in your aquarium is adequate. As a general rule of thumb, if your filter/pump(s) are not turning over the entire volume of your seahorse tank at least 3-5 times per hour, then the aquarium is under circulated. So just take the number of gallons per hour that your filter/pump/powerheads move and divide that by the capacity of your aquarium, and you can get a rough gauge of where things stand. Ideally, that calculation will come out to be 5 or above; if not, you can probably stand to increase the water flow a bit, and if the figure works out to be less than three, then you definitely need to step up the circulation. Likewise, if the number comes out to be considerably greater than 5, then you probably need to tone down the water movement somewhat, especially if you don’t have a spray bar return or waterfall return that diffuses the output from the filter. Remember, adequate surface agitation to promote efficient oxygenation and gas exchange at the air/water interface is just as important as the overall water movement.
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Keep working on your target feeding technique, Kay. Once the seahorses learn to associate your baster with their gourmet Mysis shrimp, it’s easy to lead them to the feeding station and train them to take their meals from the feeding tray. Be sure to turn down the circulation on your filter while the seahorses are feeding.

I wouldn’t transfer the percula clownfish (Amphiprion percula) and the sand sifting starfish to your 35-gallon hex tank at this time. They clownfish will compete with the seahorses for the frozen Mysis, which will complicate things at feeding time. That’s not what you want when you are still in the process of training your seahorses to accept target feeding or to eat from a feeding station. And it wouldn’t be prudent to add any more specimens to an aquarium that is experiencing a bacterial bloom and still has not yet completely adjusted to the increased bioload from all of the seahorses. For these reasons, I would not add any more specimens to your 35 hex tank for the time being.

Best wishes with all your fishes, Kay!

Respectfully,
Pete Giwojna