Although ballast water has received much attention as a source of aquatic invasive species, the aquarium and ornamental trade and associated activities are emerging as an important source for species likely to invade aquatic habitats.  The recent focus on the aquarium trade as a possible mechanism for environmentally sustainable development should be of concern to environmentalists, conservationists, ecologists, and policy makers.  Aquarium and ornamental species are selected for being hearty, tolerant of a range of conditions, and are generally sold as adults - all features that could enhance invader success.  Indeed many of the most important and costly aquatic invaders are part of the aquarium trade, including some agricultural pests such as the Applesnail.  Recent work on some of these species and especially studies that examine trade in marine species, including “live rock” provide startling results regarding the trade and risk of introduction of known harmful species and likely new invaders.  Given the threats caused by this source of invaders, there has been a call for an ecological risk assessment to address this growing threat.