Abstract

In American aquariums, touch tanks are very popular with visitors. One of the more popular touch tank displays includes sea stars and anemones. This is the typical population make up at the Florida Aquarium "No Bones Zone" touch tank. There have been many reports from biologists of sea stars in this system "melting." This change is part of a syndrome biologists and aquarists refer to as "sea star melting disease."^1-3 Causes and appropriate treatment for this condition are undefined. Previous treatments have included various topical antibiotics, topical ascorbic acid and topical triple antibiotic ointment. Earlier treatments included limb amputations to try to resolve the infections. None of these methods were effective and several animals died from the condition.

At the Florida Aquarium, the touch tank system is a flow through system with a current maintained at 50 degrees Fahrenheit. Several sea stars have succumbed to a severe ulcerative disease. The cause of death appears to be from extrusion of internal organs and loss of osmotic balance.

Three sea stars with lesions of varying severity were isolated into a back holding area that shares the same water at the display tank. Listonella pelagia (formerly Vibrio pelagia) was identified in pure culture from the lesions on one animal. Animals were treated with a sulfadimethoxine bath as 400 mg sulfadimethoxine in 5.7 L tank water for 10-15 minutes. Over a period of approx. 8 weeks lesions resolved and all three animals developed scarring and constriction of the lesions. Animals continued to be active and eat during the treatment period. To date all three animals are doing well. There is a minor recurrence on the tip of one arm on the ochre sea star. Treatments have resumed to correct this lesion.

References

1.  Harms C. 2006. Echinoderms. In: Gregory A. Lewbart (ed.) Invertebrate Medicine. Blackwell Publishing Professional, 2121 State Avenue, Ames, Iowa 50014, USA.

2.  Lewbart GA. Personal communication

3.  Noga E. Personal communication.