You’re very welcome!
Whether or not your seahorse should be dewormed depends on where you got it and whether it is a wild seahorse or it has been captive bred and raised. For instance, if you obtain wild seahorses directly from the collector or purchase your seahorses from your local fish store (LFS), then it is very important to quarantine them thoroughly before you release them in the main tank, and deworming the seahorses is typically part of the quarantine process in such cases.
The problem with obtaining seahorses from your LFS is that they are typically maintained in aquaria that share a common filtration system with all of the other fish tanks in the store. Of course, those other fish tanks house a wide selection of wild fish that have been collected from all around the world, and any pathogens or parasites those wild fishes may have been carrying can be transmitted through the common water supply to the seahorses. That makes fish from your LFS potential disease vectors for a whole laundry list of disease organisms and makes it mandatory to quarantine such specimens before they are introduced to your display tank.
If you’re going to give wild seahorses a try, or you will be bringing home seahorses from your LFS, Chris, then it’s very important to quarantine them properly and treat them prophylactically while they are in quarantine, as discussed below. For example, here is the quarantine protocol followed by the Shedd Aquarium:
Shedd Aquarium Seahorse Quarantine Protocol
The following schedule sets out the basic quarantine schedule for seahorses entering the John G. Shedd Aquarium.
Chloroquine used to be part of the quarantine process but has been discontinued as a result of sensitivity.
Seahorse quarantine = 30 days
(1) Panacur In Artemia adults or nauplii: soak at 250mg Panacur /kg food and feed out as per normal food over 3 days. Artemia can be used to gut-load other food types if necessary. Start treatment on day 10 through 13 and repeat on day 20 through 23.
(2) Praziquantel bath at 10ppm for 3 hours or 1ppm for 24 hours on Day 29.
(3) Vaccine (Alpha-Dip 2100): dip at 1 part vaccine to 9 parts water for 20 to 30 secs on Day 7 and repeat on day 14.
(4) Diagnostic dip — Osmotic (freshwater) dip on Day 30.
(5) DHADC Selco as an addition to normal food. Soak prior to feeding as per label instructions) on Days 1 through 7.
In addition, Dr. Martin Greenwell found that wild syngnathids typically arrive at the Shedd malnourished and underweight, if not emaciated, and therefore routinely require nutritional support:
"Their intestinal transit time is fairly rapid and their fat stores tend to be rather minimal. Consequently, syngnathids tend to be at a high risk for loss of body condition. With this in mind, anorexic seahorses and pipefish almost always require nutritional support. At Shedd aquarium, anorexic syngnathids or tube fed a high quality, commercial fish flake food gruel. Because of the very small, vestigial stomach, only limited volumes of growth can be administered at any given time, i.e., 0.05 to 0.10 cc for most seahorses and up to 0.25 cc for the large Hippocampus sp., trumpetfish, and the seadragons. Offering nutritional support can mean the difference between life and death for sick and/or anorectic syngnathids."
So if the new arrivals are wild seahorses, Chris, it’s important to treat them prophylactically with Panacur (fenbendazole) and a praziquantel bath to eliminate parasites while they is in your quarantine tank before you introduce them to the main tank, and it’s vital that you provide them with nutritional support if they are thin and underfed.
If the seahorses are captive-bred-and-raised specimens from a High-Health aquaculture facility such as Ocean Rider, then the quarantine protocols required for wild seahorses are unnecessary. Your seahorses will be free of pathogens and parasites when they arrive and will reach you well-fed and in top condition. There is no need to deworm them unless they subsequently show signs indicating they had picked up an infestation during their years in your aquarium.
Some of the signs to look for are a seahorse that eats well yet loses weight nevertheless. This can be an indication of cestodes (tapeworms) or intestinal flagellates. Other times, you can actually see a warm protruding from the seahorse’s vent, particularly when it is passing fecal pellets. In a case like that, Panacur (fenbendazole) is the anthelmintic (dewormer) of choice for seahorses. You can either administer the Panacur orally, as described above in the Shedd Aquarium’s quarantine protocol, or you can administer it as a bath treatment instead.
Are you worried that your seahorses may have worms or intestinal parasites of some sort, Chris? If you can advise me what symptoms lead you to suspect a problem with worms, I can help you with your diagnosis and an appropriate treatment regimen.
Best wishes with all your fishes, Chris!