It sounds like you’re doing an excellent job with the treatments. It’s certainly very encouraging that the pimplelike lesions on her snout have not worsened or begun eroding away the underlying tissue, but are actually responding to the treatments and shrinking. And it’s wonderful that she has live foods available to her in the hospital tank that she can graze on at our leisure.
Once the regimen of antibiotics has been completed, you can continue the topical treatments with a silver sulfadiazine cream and antibiotic ointment after she has been returned to the main tank. And if you let me know what antibiotics you have been using, I can provide you with instructions for gutloading live shrimp with the medication so that you can continue to treat your with antibiotics orally after she is returned to your seahorse tank without disrupting your biological filtration.
I don’t think that the stress from breeding and producing a clutch of eggs could have contributed to her problem with snout rot, however. While producing a large clutch of eggs is demanding on the female’s bodily resources (a filly can lose 30% of her body weight after depositing a clutch of eggs with her mate), the unique structure of the seahorse’s ovaries prevents this from becoming too much of a burden.
Seahorses are fractional spawners and very well adapted for producing clutch after clutch of eggs. Females maintain a spiraling assembly line of developing oocytes (egg cells) at all times, only a portion of which are fully mature and are released at each mating (Vincent, 1990). This differs from the reproductive strategy of most fishes, which are multiple spawners that release all their eggs each time they mate and then start over, maturing an entirely new clutch of eggs from scratch for the next spawning.
The structure of the ovaries is unique to syngnathids. They are paired organs, which join to form a single oviduct (the seahorse’s version of a Fallopian tube) just before the urogential pore (Vincent, 1990). Oocytes spiral out from the center of each ovary, creating a coiled sheet of developing eggs at differing stages of growth (Vincent, 1990). The earliest or primordial eggs arise from the germinal ridge that runs the entire length of the ovary, and lie at the center of the coil from which they spiral out as they develop so that the fully mature eggs are the furthest from the center of rotation (Vincent, 1990). Roughly 20-25% of the outermost eggs in this ovarian assembly line are mature, ready to be discharged during ovulation and deposited with the male (Vincent, 1990). Thus, fully 70-75% of the female’s developing eggs are retained in the ovaries after mating, so a new clutch of eggs will mature relatively quickly and lie in readiness for the next mating cycle.
Seahorse ovaries are always active, busy creating and developing new eggs (oogenesis), forming the yolk (vitellogenesis), and resorbing any mature ova (atresia) leftover after mating or at the end of the breeding season (Vincent, 1990). Eggs in all 4 stages of development can be found in the ovaries throughout the year.
In short, breeding and producing large numbers of eggs is not so stressful on a female seahorse dead it could ordinarily result in illness. Most cases of snout rot are secondary infections resulting from a mechanical injury to the snout. They may have bumped or scraped their snout on a bacteria laden substrate while feeding off the bottom, or accidentally ingested a bit of gravel that irritated their tubular snout before it could be expelled. (Which is one more reason it is a good idea to train your seahorses to eat from a feeding station, which provides a sanitary surface from which they can feed.) Occasionally, snout rot will develop as a manifestation of a systemic infection, but it is most often associated with secondary infections following some sort of injury or problem with protozoan parasites.
Best of luck with the treatments, Jeff. Here’s hoping your female makes a complete recovery and is soon back in the main tank with a mate.