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 macroalgaes, 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 there 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.
Try to determine if that’s the case, Billie, because prompt treatment is necessary when seahorses developed buoyancy problems, which are most often due to gas bubble syndrome (GBS). There is a simple test you can do in order to tell if your seahorse is having a problem with positive buoyancy: just gently dislodge him from his perch near the overflow, cup him in your hand, and release him at the bottom of the aquarium. If he can stay near the bottom and swim about normally, then all is well, but if he has to fight to stay down and eventually bobs up to the surface again like a cork, then you’ll know that he’s in trouble and we can treat him for GBS to relieve the problem.
There is one other potential problem you should be aware of as well, Billie. 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. If there has been an ammonia or nitrite spike in the aquarium, giving the seahorse a bath or dip in methylene blue can help correct the problem.
Please get back to me as soon as possible when you have had a chance to determine if the seahorse is having a problem with positive buoyancy or is experiencing respiratory distress and struggling to get enough oxygen.
Best wishes with all your fishes, Billie. Here’s hoping your seahorse has just developed an affinity for that water pump and that you can cure him of this bad habit without too much trouble.