Medical Management of Syngnathids with Buoyancy Disorders
IAAAM Archive
Shirley Yeo Llizo
Houston Zoo
Houston, TX, USA


The seahorses and seadragons belong to the family Syngnathidae. They are shy animals, and thrive better in tanks of the same species where food competition is not an issue. Long grassy furniture is necessary for them to anchor with their tails as constant swimming can lead to exhaustion. They are voracious eaters and need a constant supply of live food.2

Case Report #1: On 2 October 2003, a male Potbelly Seahorse (Hippocampus abdominalis) was reported to have been floating near the water surface intermittently for the past 2 weeks. On physical exam, the specimen was struggling to maintain a normal posture and buoyancy. The brood pouch was moderately distended with multiple air pockets or "pseudocysts" present along the tail.1 Treatment consisted of lavaging the brood pouch with sterile saline in the event there was any leftover reproduction material or abscess. The pouch appeared clean. The pouch wall was aspirated with a 1 ml syringe with a 27 gauge needle, and immediately visualized the wall thickness subsiding. The air pockets along the tail were also aspirated, and they also subsided. Ceftazidime was initiated at 22 mg/kg, 1 mg IM every 5 days for 5 doses.1 Additionally, acetazolamide, a carbonic anhydrase inhibitor, reconstituted to 50 mg/ml solution, was initiated at 6 mg/kg (range 3-6 mg/kg) every 5 days for 5 doses.1 There was noticeable improvement after treatment as he was more stable. The following day, he was still close to the surface. More air pockets on the brood pouch and tail were aspirated. This continued for the next 10 days with variable severity in the buoyancy disorder. Treatment with injectable drugs as well as aspiration of air pockets was performed. On the tenth day, there was significant improvement in his posture and buoyancy, anchored to the props at the bottom of the tank in a normal posture. Treatment was completed, and his problem was resolved on 18 November 2003. He remains normal to this day.

Case Report #2: On 10 October 2003, a male Longsnout Seahorse (Hippocampus reidi) presented with a mild buoyancy disorder. He was floating near the water surface. On physical exam, there were multiple "pseudocysts" on the ventral aspect of the distal tail. These were aspirated. Treatment consisting of Ceftazidime and acetazolamide was initiated as in case report #1. A slight improvement was seen after the procedure. Within 9 days, the buoyancy disorder was not observed. Further treatments with Ceftazidime and acetazolamide were discontinued. However, he was found dead a week later. Histopathology described a granulomatous nephritis and hepatitis with post-mortem autolysis.

Case Report #3: On 19 October 2003, a female Weedy Seadragon (Phyllopteryx taeniolatus) presented with a tiny growth on the left side of the lower lip. She was spending most of her time near the water surface in a vertical posture. Under manual restraint, a brief exam was performed. The whitish "polyp" was manipulated with a 27 gauge needle and punctured. No discharge was obtained. The lip and mouth function did not appear to be affected. She was monitored for food intake. For a week, she was eating sporadically, and spending most of her time near the water surface with the snout above the water. She appeared thin. An exam under sedation with MS-222 was elected to allow a more thorough exam without added stress to her. The polyp was unchanged, and the snout and mouth were patent without evidence of blockage. There were no other abnormal findings. Rather than prolong the procedure, it was decided that radiographs would not be done at this point. Radiographs were taken 2 days later without anesthesia. There were no abnormal findings. Her weight was 27.9 g. Treatment with Ceftazidime was initiated (same regime as above), and she also received vitamin B complex 0.01 ml IM once weekly for 4 doses. Additionally, she was tube fed with a seafood mixture gruel, initially using a 3.5 French tomcat catheter (closed end) but although this had a suitable bore size, it did not reach beyond the pharyngeal region (14 cm) so a size 5 French feeding tube/urethral catheter was used instead. Her condition deteriorated over the next several days. She became anorexic, and despite the daily tube feedings, she was cachetic. She was also floating horizontally near the water surface, and as her condition worsened, she sank to the bottom, and finally died. Histopathology described a non-identifiable sporozoan-like organism within the biliary ducts which might have been a contributing factor in her demise, encapsulated granulomas within the hepatic parenchyma which could not be determined with special stains, and finally, the mass on the lip appeared to be a benign hemangioma of unknown etiology. No viral inclusions were histologically evident.


The author wishes to thank the veterinary and aquarium staff for their assistance and dedication in the medical handling of these cases.


1.  Greenwell MG. 2002. Syngnathid Health Management. In: Bull, C.D. (ed.). Seahorse Husbandry in Public Aquaria 2002 Manual. P. 21.

2.  Stoskopf M. 1993. Taxonomy and Natural History of Marine Tropical Fishes. In: Stoskopf, M. (ed.). Fish Medicine. W. B. Saunders Co, Philadelphia. Pp. 610-611.

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Shirley Yeo Llizo

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