Abstract

Idiopathic gaseous exophthalmia is a condition that often affects fish in temperate marine aquaria. The condition is usually characterized by a dramatic unilateral exophthalmos with an accumulation of gas in the posterior chamber of the eye. The authors have observed this condition in three species of rockfish; black rockfish, Sebastes melanops, copper rockfish, S. caurinus, and dark blotched rockfish, S. crameri, held at the Hatfield Marine Science Center Aquarium and the Oregon Coast Aquarium. Aspiration of the gas from the posterior chamber of the exophthalmic eye followed by a unilateral pseudo-branchectornyipsilateral to the affected eye eliminated the exophthalmia and appears to prevent recurrence. We have used this procedure to successfully treat three fish diagnosed with idiopathic gaseous exophthalmia. In each case these fish have resumed feeding and have been successfully returned to public display within six weeks of undergoing the procedure. We hypothesize that the etiology of this condition is related to a malfunction in the ocular oxygen concentrating mechanism.