Belly sliders?
This article from 2007 is now available in English. Well worth a read. Gas filling of the swimming bladder of south American annual fish larvae(Cyprinodontiformes; Rivulidae)Pablo A. Calviño (1), Felipe Alonso (1) and Jorge Sanjuán de Torres (2)(1) Study Group of Killi Club Argentino (KCA), Independencia 443, Villa Ballester 1653, BuenosAires, Argentina. e-mail: pablocalvin@yahoo.com.ar. (2) SEK, Spanish Killis Society.