Abstract
Leafy (Phycodurus eques) and weedy seadragons (Phyllopteryx taeniolatus), members of the family Syngnathidae, were named because of their resemblance to Chinese mythical dragons.3 Endemic to the waters of southern Australia, these animals have become popular display animals for zoos and aquaria. As a result, much interest has been generated in the care of these unusual animals. Only three diseases have previously been reported in seadragons: epitheliocystis, Vibrio septicemia, and coccidiosis.2,4,6 Maintaining proper husbandry is vital to the health of these animals. Important considerations include temperature, tank size, lighting, and feeding.2,5 The information compiled here represents the experience from four institutions. The findings reported here were confirmed at necropsy (Tables 1–3).
Table 1. Etiologic diagnoses on postmortem exams
|
Leafy seadragons
|
Number affected
|
Weedy seadragons
|
Number affected
|
|
Uronemiasis
|
5
|
Coccidiosisa
|
8
|
|
Bacterial sepsis
|
2
|
Uronemiasis
|
5
|
|
Mycobacteriosis
|
2
|
Bacterial sepsis
|
5
|
|
Neoplasia
|
1
|
Fungal sepsis
|
1
|
|
Oxygen supersaturation
|
2
|
|
|
aThe role of the coccidian infection in the clinical course of these animals is unknown.
Table 2. Leafy seadragons at the four institutions
|
Institutions
|
Total animals (live and dead)
|
Total mortalities
|
Mortalities with etiologic diagnoses
|
|
Dallas World Aquarium
|
28
|
11
|
7
|
|
Florida Aquarium
|
7
|
0
|
0
|
|
New England Aquarium
|
8
|
4
|
3
|
|
Shedd Aquarium
|
5
|
0
|
0
|
Table 3. Weedy seadragons at the four institutions
|
Institutions
|
Total animals (live and dead)
|
Total mortalities
|
Mortalities with etiologic diagnoses
|
|
Dallas World Aquarium
|
8
|
5
|
5
|
|
Florida Aquarium
|
8
|
3
|
3
|
|
New England Aquarium
|
6
|
5
|
4
|
|
Shedd Aquarium
|
14
|
10
|
5
|
Uronemiasis is the most common etiologic diagnosis detected histologically in leafy seadragons housed at the contributing institutions. Although coccidiosis is a common finding in weedy seadragons, pathogenicity is unknown. The presence of coccidian oocysts does not indicate pathologic disease, but may be an incidental finding as seen in other species of animals.1 A neoplasm, hemangiosarcoma, was observed in one leafy seadragon. Although not listed as a cause of death, ingestion of gravel may present a potential danger by causing an obstruction. The gravel selected should be large enough to prevent ingestion by animals of all sizes exhibited. Hopefully with the sharing of information on health and husbandry, zoos and aquaria can provide even better care of these unique animals.
Acknowledgments
The authors would like to thank the following individuals for their contributions to this poster: Michael J. Kinsel and the University of Illinois Pathology Program, Casey Sugarman, Robert Cooper, Michael Callahan of the New England Aquarium, and Daryl Richardson, Paula Powell of the Dallas World Aquarium, and Alex Slater of the Florida Aquarium.
Literature Cited
1. Georgi JR, Georgi ME. Parasitology for Veterinarians. Philadelphia, PA: W.B. Saunders Company; 1990:84–90.
2. Langdon JS, Elliott K, Mackay B. Epitheliocystis in the leafy sea-dragon. Austr Vet J. 1991;68(7):244.
3. Mackay B. Seadragons in the wild and captive environments. Third International Aquarium Congress. Boston, MA. 1993:207–217.
4. Osborn A, Stamper MA, Reimschuessel R, Greenwell M, Zwick L, Kinsel MJ. Coccidiosis in the weedy seadragon (Phyllopteryx taeniolatus). In: Proceedings of the International Association for Aquatic Animal Medicine (IAAAM). Boston, MA. 1999;30:77–80.
5. Powell P. The care and husbandry of the leafy seadragon. In: Proceedings of the American Zoo Aquarium Association. Albuquerque, NM. 1995:440–446.
6. Upton SJ, Stamper MA, Mumford SL, Osborn AL, Zwick L, Kinsel MJ, Overstreet RM. A new species of Eimeria (Apicomplexa, Eimeriidae) from the common sea dragon, (Phyllopteryx taeniolatus) (Osteichthyes: Syngnathidae). Dis Aquat Organ. 2000;43:55–59.