Florida Seahorse Keepers

Dear Denise:

Howdy, Denise! This post has been up for a while now and still has no replies from fellow seahorse keepers in Florida, so I thought I would jump in and offer you a couple of suggestions on the matter.

As you know, the Mustangs and Sunbursts (Hippocampus erectus) prefer water temperatures in the range of 72°F-77°F, and they can begin to experience heat stress and associated health problems when the water temperature approaches 80°F or above for any length of time. So I can certainly understand why you are concerned if your tank is holding steady right now at 77°F in the wintertime. It appears that you may be faced with some dangerous temperature spikes in your 37-gallon tank during those inevitable summertime heat waves in Florida.

However, Denise, there is a simple technique that you can use to drop the water temperature in an aquarium by at least 3°F-5°F without the use of a chiller: either remove the cover or hood altogether, if possible, or at least keep it the cover tilted open as far as possible. When the aquarium is tightly sealed, heat is trapped underneath the cover and the water temperature rises as a result. Removing the cover or hood, or at least cracking it open as much as possible, allows the trapped heat to escape and equalize with the ambient air temperature. It also reduces the humidity, which results in more efficient gas exchange at the air/water interface; the dissolved exigent levels are increased and the carbon dioxide levels are reduced as a result, which, in turn, helps to stabilize the aquarium pH in the proper range. If possible, you can simply remove the cover or hood altogether since there is no danger that your seahorses will jump out of the tank. If not, you may have to settle for lifting the lid part way the way you would when accessing the tank to feed the fishes, or by cracking it open.

You will find that the water temperature drops by several degrees if you can remove the cover or aquarium hood altogether, and it should drop at least 2°F-3°F even if you could only cracked the lid open. For example, this is what Ambrose, a seahorse keeper with a JBJ nano tank, reports in that regard:

"… my tank set up is a JBJ nano cube. I believe that its 20 in long, by 20 inch wide, and is 18 inches deep. It’s a closed top system that runs a 150 watt metal halide bulb. Heat with this tank has been an issue almost the whole time with this tank. And on the hottest days on the year the tank has seen temp as high as 82-83 degrees. I’ve found that leaving the tank lid cracked open has drastically reduced the tanks temp by 3-4 degrees. So that’s the way I’ve been leaving it lately (open top),the tank now stays at a steady 78-79 degrees constantly. That’s another trick that I only recently discovered…"

Notice that Ambrose was only able to leave the aquarium lid cracked open, but even so was able to lower the water temperature by around 4°F. That’s something that might be worth a try with your new aquarium, Denise.

The only drawback to this technique is that it increases the rate of evaporation so that you need to top off the tank with freshwater more frequently, but that’s merely a minor inconvenience.

In Florida, during a prolonged heat wave, simply leaving the aquarium would off or keeping the aquarium lid wide open may not drop the water temperature sufficiently, in your case, Denise. If that proves to be true, there are a couple of other simple tricks that you might consider as well.

For example, some hobbyists keep their fish room air-conditioned and adjust the air conditioning to keep the air temperature in the room at about 75°F or a bit below. The water temperature in your fish tanks then tends to stabilize at around that temperature range as well, and with the aquarium hood off or the aquarium lid left wide open, your tank shouldn’t get much warmer than about 77°F-78°F with a room air conditioner set at 75°F.

Or, if air conditioning your fish room is not a possibility, Denise, you can further reduce the water temperature via evaporative cooling instead. One simple way to drop the water temp in your aquarium is to position a small fan so it blows across the surface of the water continually (Giwojna, Oct. 2003). This will lower the water temperature several degrees through the phenomenon of evaporative cooling (just be sure to top off the tank regularly to replace the water lost to evaporation, which will be considerable. Installing an automatic top off system makes sense if you will be relying on evaporative cooling to maintain the water temperature.). Leaving the cover/hood and light off on your seahorse tank in conjunction with evaporative cooling can make a surprising difference. (A hood or cover tends to trap heat and hold it in the tank, so removing the cover or lid from the aquarium can make a surprising difference in the water temperature, and is safe to do with seahorses since they do not jump at all.)

Most hobbyists find that small, clip-on fans that are equipped with a cord and all ready to go right off the shelf are the most convenient when they need to cool down one of my tanks, as Leslie Leddo described below:

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Fans work great for decreasing tank temps. Small 6 to 8 inch plastic electric clip on fans are available at most home improvement centers and places like Longs or Rite Aide. They can be clipped on to the tank rim and adjusted so that the air from the fan blows across the surface of the water rippling it a bit. This works very well. I would suggest 2, one on either side of the tank.

It does increase evaporation quite a bit so you will need to top off more frequently.

It is also a good idea to use a heater set at the the low end of the goal range. If your tank is 78 without a heater start by setting it to 76 with the fans running and decrease it by 2 degrees every day until you figure out just how much the fans will bring that temp down. I am guessing with 2 fans you should be able to keep the temp about 75, which should be just perfect.

HTH,

Leslie
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While reducing the water temperature via evaporative cooling, I should also caution you to observe all the usual precautions to prevent shocks and electrical accident when you are using an electric fan or any other electrical equipment on your aquarium, Denise.

One such precaution is to install an inexpensive titanium grounding probe in your aquariums. That will protect your seahorses and other wet pets from stray voltage and should also safeguard them electrocution in the event of a catastrophic heater failure or similar accident..

But the best way to protect you and your loved ones from electrical accidents around the fish room is to make sure all the outlets are equipped with Ground Fault Circuit Interrupters. And it’s a good idea to make sure all your electrical equipment is plugged into a surge protector as well to further protect your expensive pumps, filters, heaters, etc. from damage. Some good surge protectors, such as the Shock Busters, come with a GFCI built right into them so you can kill two birds with one stone. So when you set up your cooling fan(s) on the aquarium, be sure they’re plugged into a grounded outlet with a GFCI or a surge protector with GFCI protection.

Hopefully one of these techniques will work very well for your 37-gallon seahorse setup this summer, Denise.

Best of luck reducing the water temperature to the desired range quickly and easily, Denise.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support