It’s difficult to say what may be causing the increase in the respiratory rate of your small Hippocampus kuda, since many different factors may affect the breathing rate of your seahorses, but since it’s a new arrival, my best bet is that it is stressed out by its strange, new surroundings.
The first things you should do are to increase the aeration and surface agitation in your tank to raise the levels of dissolved oxygen and lower the levels of dissolved CO2 in the aquarium water, and then to double-check all of the usual aquarium parameters.
In other words, Alexis, make sure that the water temperature, pH, and levels of ammonia, nitrite, and nitrate are where they should be. Summertime heat waves this time of year can cause a spike in the water temperature of the aquarium, and the higher the water temperature, the faster the metabolism of the seahorses will be so the more oxygen they need, and the less dissolved oxygen the aquarium water can hold.
In my experience, tropical seahorses can begin to experience heat stress and associated health problems when the water temperature approaches 80°F or above for any length of time. If your water temperature is creeping up towards that level in the month of July, Alexis, you should gradually lower the water temperature by no more than 2°F daily until it’s back in the normal range again.
Here are some of the other factors that can influence the breathing rate of your seahorses, Alexis:
Your seahorses’ respiration rate may increase naturally when they are feeding, actively courting, being handled, or excited in general, and then return to their normal resting respiratory rate afterwards. That’s natural and nothing to be concerned about.
Likewise, a seahorses respiration rate will increase whenever they are stressed out. In your case, it seems likely that the small Hippocampus kuda is stressed, which could result from heat stress or a spike in the ammonia or nitrite levels, or because of a drop in dissolved oxygen in the aquarium water.
Here is some additional information that discusses the breathing rate in seahorses and the factors that affect their breathing:
Normal Respiration vs. Respiratory Distress
Symptoms of respiratory distress are ordinarily pretty obvious and you should have no trouble determining when your seahorse is laboring or struggling to breathe. For example, seahorses that are stressed or suffering from gill disease or parasites that attack the gills will exhibit rapid respiration, labored breathing, huffing, panting, yawning or coughing behavior, and other indications of respiratory distress. So familiarize yourself with your seahorse’s normal respiration rate when they are comfortable in healthy, which will vary somewhat with water temperature and their activity level or degree of arousal/excitement, and subsequent changes in their normal breathing pattern can alert you to a possible problem.
There is no simple answer to the question, “What is the normal breathing rate for seahorses?” Their respiration rate will vary according to the levels of oxygen and carbon dioxide in the aquarium, the water temperature, their metabolic rate, their activity level, and their emotional state.
Unlike human beings, which are homeothermic and maintain homeostasis at all times, seahorses are of course cold-blooded creatures, so their metabolic rate is determined largely by the water temperature. The warmer the water temperature, the higher their metabolism and the greater their oxygen demand becomes, and their breathing rate goes up according. At lower water temperatures, the seahorse’s metabolism and oxygen demand are reduced, and their breathing rate slows.
The level of oxygen in the atmosphere that we breathe is quite stable and constant, but that’s not the case with the level of oxygen in an aquarium. For example, the warmer the aquarium water is, the less dissolved oxygen it can hold, and the higher the salinity of the aquarium water, the less dissolved oxygen it can hold. So the amount of oxygen in the water varies with the aquarium temperature and salinity or specific gravity.
Likewise, the levels of oxygen and carbon dioxide in an aquarium varies from day to night due to the photosynthesis performed by macroalgae and zooanthellae. When the aquarium reflector is on, providing plenty of light, the algae and plants in the aquarium take in carbon dioxide and release oxygen as a byproduct of photosynthesis. As a result, the pH of the water and the dissolved oxygen levels rise throughout the day, while the level of dissolved carbon dioxide drops.
On the other hand, during the night when the aquarium light is turned off and no photosynthesis takes place, the plants will begin to take in oxygen and give off carbon dioxide. This has exactly the opposite effect — the pH of the aquarium water and the level of dissolved oxygen drop at night, while the amount of dissolved carbon dioxide rises. This can occasionally become a problem in a small, poorly circulated, closed-system aquarium that is very heavily planted if the oxygen levels drop so much during the night and the carbon dioxide levels rise so high that the seahorses have difficulty breathing and getting enough oxygen.
So in an aquarium where the dissolved oxygen levels are low and/or the carbon dioxide levels are high, seahorses will exhibit very rapid respiration.
Seahorse setups are often more 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, aggravating the situation.
Seahorses are more vulnerable to the 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, seahorses are thus especially vulnerable to low oxygen levels and asphyxia.
Warm water temperatures exacerbate such problems in the aquarium. Elevated water temperatures increase the metabolism of seahorses, and therefore their consumption of oxygen, at the same time that the rise in temperature is reducing the amount of dissolved oxygen the water can hold. That double whammy creates a dangerous situation for seahorses and may well result in respiratory distress and rapid, labored breathing.
For best results with most tropical seahorses, strive to maintain stable water conditions in your seahorse tank within the following aquarium parameters at all times:
Temperature = optimum 72°F-75°F (22°C-24°C).
Specific Gravity = range 1.022 – 1.026, optimum 1.0245
pH = 8.2 – 8.4
Ammonia = 0
Nitrite = 0
Nitrate = 0-20 ppm; optimum 0-10 ppm
Provide good surface agitation and aeration in order to promote better oxygenation and facilitate better gas exchange at the air/water interface.
Best of luck with your new Hippocampus kuda, Alexis.
Pete Giwojna, Ocean Rider Tech Support