Good day, mate!
I’m sorry to hear that your female Tigersnout (Hippocampus elongatus) seems to be having a tough go of it. Rapid respirations and a lack of energy can be indications that a seahorse is not getting enough oxygen, and I would recommend treating your female with methylene blue, as discussed below:
Commonly known as "meth blue" or simply "blue," this is a wonderful medication for reversing the toxic effects of ammonia and nitrite poisoning. Methylene blue transports oxygen and aids breathing. It facilitates oxygen transport, helping fish breathe more easily by converting methemoglobin to hemoglobin — the normal oxygen carrying component of fish blood, thus allowing more oxygen to be carried through the bloodstream. This makes it very useful for treating gill infections, low oxygen levels, or anytime your seahorses are breathing rapidly and experiencing respiratory distress. It is the drug of choice for treating hypoxic emergencies of any kind with your fish. However, methylene blue will destroy nitrifying bacteria so it should be used in a hospital tank or as a brief bath or dip only (if used in an established aquarium, it will impair the biological filtration and the tank may need to be cycled all over again).
Here is some more information that explains how to treat with methylene blue properly:
If you can obtain the Kordon brand of Methylene Blue (available at most well-stocked local fish stores here in the US), the instructions for administering it as a very brief, concentrated dip are as follows:
For use as a dip for treatment of fungus or external parasitic protozoans and cyanide poisoning:
(a) Prepare a nonmetallic container of sufficient size to contain the fish to be treated by adding water similar to the original aquarium.
(b) Add 5 teaspoons (24.65 ml) per 3 gallons of water. This produces a concentration of 50 ppm. It is not recommended that the concentration be increased beyond 50 ppm.
(c) Place fishes to be treated in this solution for no longer than 10 seconds.
(d) Return fish to original aquarium.
When you administer such a dip, hold the seahorse in your hand throughout the procedure and time it closely so that the dip does not exceed 10 seconds.
And here are Kordon’s instructions for administering the methylene blue in a hospital tank if longer-term treatment seems appropriate:
As an aid in reversal of nitrite (NO2-) or cyanide (CN-) poisoning of marine and freshwater aquarium fishes:
(a) Remove carbon filter and continue to operate with mechanical filter media throughout the treatment period.
(b) Add 1 teaspoon of 2.303% Methylene Blue per 10 gallons of water. This produces a concentration of 3 ppm. Continue the treatment for 3 to 5 days.
(c) Make a water change as noted and replace the filter carbon at the conclusion of the treatment.
See the following link for more information on treating with Kordon’s Methylene Blue:
Click here: KPD-28 Methylene Blue
If you obtained a brand of methylene blue other than Kordon, just follow the instructions the medication comes with.
One other tip: if you ever need to handle seahorses to administer first aid measures or treat them in a hospital tank, it’s best not to net them when you are manipulating the seahorse:
I do not like to use an aquarium net to transfer or manipulate seahorses, since their delicate fins and snouts can become entangled in the netting all too easily. I much prefer to transfer the seahorses by hand. Simply wet your hand and fingers (to avoid removing any of the seahorse’s protective slime coat) and scoop the seahorses in your hand. Allow them to curl their tail around your fingers and carefully cup their bodies in your hand to support them while you lift them out of the water. When you gently immerse your hand in the destination tank, the seahorse will release its grip and swim away as though nothing out of the ordinary has happened.
Composed of solid muscle and endowed with extraordinary skeletal support, the prehensile tail is amazingly strong. Indeed, large specimens have a grip like an anaconda, and when a 12-inch ingens or abdominalis wraps its tail around your hand and tightens its hold, its vise-like grip is powerful enough to leave you counting your fingers afterwards!
In fact, it can be quite difficult to remove an attached seahorse from its holdfast without injuring it in the process. Never attempt to forcibly detach a seahorse from its hitching post! When it feels threatened, it’s instinct is to clamp down and hold on all the tighter. When you must dislodge a seahorse from its resting place for any reason, it’s best to use the tickle technique instead. Gently tickling the underside of the tail where it’s wrapped around the object will usually induce the seahorse to release its grip (Abbott, 2003). They don’t seem to like that at all, and will quickly let go to move away to another spot. Once they are swimming, they are easy to handle.
Since your skinny female has been off her feed, in addition to administering methylene blue as a bath, you should also consider performing a series of water changes and tempting the seahorse with live foods, as explained below:
For starters, I have listed some of the factors that are commonly known to contribute to a loss of appetite in seahorses:
(1) deteriorating water quality.
(2) low oxygen and/or high CO2 levels.
(3) a deficiency of trace elements and minerals.
(4) various disease processes — in particular, internal parasites.
Regardless of how your water chemistry appears right now, a good place to start addressing this problem would be to perform a 25%-35% water change immediately to safeguard the water quality and replenish depleted trace elements and minerals. (At first glance your aquarium parameters may look great, but there are some water quality issues that are difficult to detect with standard tests, such as a decrease in dissolved 02, transitory ammonia/nitrite spikes following a heavy feeding, pH drift, a deficiency and trace elements/minerals, or the gradual accumulation of detritus. A water change and cleanup is a simple preventative measure that can help defuse those kinds of hidden factors before they become a problem and stress out your seahorses. These simple measures may restore your water quality as well as your seahorses’ appetite.)
Be sure to check your dissolved oxygen (O2) level in addition to the usual pH, ammonia, nitrite and nitrite readings.. A significant drop in O2 levels (6 – 7 ppm is optimal) or rise in CO2 levels is very stressful yet easily corrected by increasing surface agitation and circulation to promote better oxygenation and gas exchange. Add a shallow airstone just beneath the surface if necessary and increase the circulation throughout your tank it possible.
Whether the beneficial effects are due to improving water quality or replenishing depleted trace elements or something else altogether, performing a major water change as described above often sets things right when seahorses are off their feed for no apparent reason.
In the meantime, while you are working on your water quality, by all means get some live foods to keep your finicky female eating and see if you can fatten her up a bit. Any live foods that are readily available — enriched adult brine shrimp, live ghost shrimp that are small enough to be swallowed, feeder shrimp, newborn guppies or mollies, Gammarus amphipods, copepods, you name it — is worth a try. Just get some good meals into her ASAP to build up her strength and help her regain her conditioning.
In short, I would recommend treating your female H. elongatus with methylene blue, performing a series of small water changes, increasing the aeration/oxygenation in the aquarium, and offering live foods to help build up our strength again.
Best of luck restoring your skinny seahorse to good health again.