There are several commercial suppliers of selective agars for the isolation of Aeromoas spp. these include BD, HiMedia Laboratories, labM, Sigma-Aldrich, Merck Millipore, Guenter Keul GmbH, LABORATORIOS CONDA, etc. Are you looking for a commercial supplier? Most of these companies sell the dehydrated media that you would have to prepare.
Apart from commercial media, an easy approach is to add ampicillin (10 mg/litre) to any differential media, as the starch ampicillin agar (Palumbo et al, 1985) or ampicillin dextrin agar (Havelaar et al, 1987). You can find those publications easily through a web search.
Definitively, ampicillin is the best selective agent for isolation of motile aeromonads You have to keep in mind that some strains can be susceptible to ampicillin, but in my experience is of minor importance, unless you are interested in study those particular strains.