Seahorse sticks head out of water

Dear Eric:

Sometimes seahorses develop a bad habit of perching high up in the aquarium on some piece of apparatus that strikes their fancy for reasons obvious only to themselves. I don’t know how many times over the years I’ve had seahorses ignore all my artfully arranged aquascaping and handpicked, thoughtfully placed finger sponges, colorful branching corals, lush beds of macroalgae, and gorgeous gorgonia, only to adopt an unsightly siphon tube or the damned heater cord as their favorite hitching posts instead!

As you know, our amazing aquatic equines — especially the stallions — will often choose one particular hitching post as their home base and spend much of their time perched right there (think of your Dad hunkered down in his favorite easy chair in the den). Once they adopt a favorite base of operations like this, they will often proceed to change coloration to match their preferred resting spot. So I always take great pains to encourage my ponies to adopt one of the more vivid pieces as a favorite holdfast. Needless to say, it’s tremendously frustrating and annoying when they eschew all the primo hitching posts I’ve so carefully selected and arranged for them in favor of some piece of mechanical apparatus haphazardly dangling inside their tank! Doh!

Other times seahorses will begin perching on the highest point in the aquarium they can anchor to because they have developed a problem with positive buoyancy (i.e., the tendency to float). They will perch high up when that happens because it simply requires too much effort and energy for the seahorse to fight against its buoyancy in order to swim normally or to remain near the bottom, as they usually do. It’s not normal for a seahorse to expose part of its anatomy to the air, and the fact that yours is perching with its coronet clear out of the water, makes me suspect that it is having a problem with positive buoyancy that prevents it from staying submerged.

But I don’t think that’s the case with your female, Eric, since she is spending half of her time on the bottom of the tank as usual.

There is one other potential problem you should be aware of as well, Eric. Sometimes seahorses will take to perching on the output from a water pump or filter and sticking their heads and bodies right in the water stream that is emerging because they are having trouble breathing and that’s where the levels of dissolved oxygen in the aquarium are the highest. Seahorses can develop such breathing problems when they have gill parasites or a gill infection, or when the dissolved oxygen levels in the aquarium are too low (or the CO2 levels are too high), or when they are suffering from ammonia poisoning or nitrite toxicity, which alters the hemoglobin in their blood so that it can no longer transport oxygen.

We sometimes see oxygen levels dropping too low in our seahorse tanks during summertime heat waves, since the warmer the water temperature becomes, the less dissolved oxygen it can hold. If you suspect the seahorse is having trouble getting enough oxygen, try increasing the aeration in the aquarium while you gradually lower the water temperature.

But I doubt that that’s the case with your female, Eric, since she is apparently the only seahorse that is exhibiting this odd behavior.

One other possibility is that she may be hanging out atop the mortar for your skimmer because she is using it as a safe haven to avoid aggression from one of her tankmates. Have any of the other seahorses exhibited any hostility towards your female erectus lately, sir?

Or perhaps your male erectus has been a little too persistent in his attempts to encourage her to mate so she has taken to retreating to the top of the skimmer motor in order to escape his unwanted attention when she needs a break?

Whatever the reason, you’ll want to discourage your female from spending too much time at the top of your tank, sir, since that can make are more susceptible to problems with gas bubble syndrome (GBS).

Increased water depth is protective against GBS because the deeper you go and the greater the water pressure becomes, the more dissolved gases the water (and your blood) can hold in solution. By the same token, the shallower you go and the less water pressure there is, the less dissolved gases the water can hold and the more likely gas is to come out of solution and form gas emboli (i.e., seed bubbles) in the blood and tissues. This means that there is a definite relationship between Gas Bubble Syndrome (GBS) in seahorses and aquarium depth. To put it in a nutshell, the shallower the water depth, the more likely GBS is to occur.

The point is that the greater hydrostatic pressure at increased depth is known to protect seahorses against GBS, whereas the reduced hydrostatic pressure in shallow aquaria is known to be conducive to GBS. So spending too much time at the top of the tank is something you will want to prevent. Is there a way that you can screen off or shield your skimmer motor so it is inaccessible to the seahorses?

Best wishes with all your fishes, Eric. Here’s hoping your seahorse has just developed an affinity for the skimmer motor and that you can cure her of this bad habit without too much trouble.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support