Inter-Research > DAO > v151 > p23-27  
Diseases of Aquatic Organisms

via Mailchimp

DAO 151:23-27 (2022)  -  DOI:

Histopathological description of iridophoromas resembling skin nodule syndrome in Siamese fighting fish Betta splendens

Jorge Orós1,*, Simon L. Priestnall2, Alejandro Suárez-Bonnet2

1Department of Morphology, Veterinary Faculty, University of Las Palmas de Gran Canaria, 35413 Arucas (Las Palmas), Spain
2Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield AL9 7TA, UK
*Corresponding author:

ABSTRACT: Intensive breeding of the Siamese fighting fish Betta splendens, a species that inhabits marshlands in Thailand and other countries in south-east Asia, was traditionally focused on game fighting because the males are very territorial, but has evolved to become mainly devoted to ornamental purposes. Recently, a preliminarily named ‘skin nodule syndrome’ (SNS) has been described affecting this fish species in Thailand, with multiple bacterial infections suggested, including 4 species of Mycobacterium spp., although the etiology remains elusive. Here we describe the histopathological and immunohistochemical characteristics of 2 iridophoromas in 2 male Siamese fighting fish that strongly resemble the lesions described for SNS. Immunohistochemical analysis yielded negative results for Melan-A, PNL-2, and S-100, likely due to species-specific reasons. The results for molecular detection of mycobacterial DNA were also negative in both cases. The published histological lesions of SNS are very similar to the 4 chromatophoromas that have been reported affecting this species since 2015. Taken together with the present cases, we hypothesize that the preliminarily named SNS in fighting fish may be characterized as invasive chromatophoromas, although the true etiology remains to be elucidated and could include infectious and non-infectious causes. Further studies are necessary to examine whether commercial breeding of Siamese fighting fish has resulted in a possible genetic origin.

KEY WORDS: Betta splendens · Chromatophoroma · Immunohistochemistry · Iridophoroma · Siamese fighting fish

Full text in pdf format
Supplementary material
Cite this article as: Orós J, Priestnall SL, Suárez-Bonnet A (2022) Histopathological description of iridophoromas resembling skin nodule syndrome in Siamese fighting fish Betta splendens. Dis Aquat Org 151:23-27.

Export citation
Share:    Facebook - - linkedIn

 Previous article Next article