The issue with passing on animals that, one or a few generations back, originated as illegal is certainly complicated. There are quite a lot of animals where this is the case; marine iguanas and earless monitors have already been mentioned. The monitor has now been bred at a number of places and although it remains rare, it could be a species that end up being fully established. Not much of a display animal, however. The
Swiss marine iguanas have been discussed before on zoochat (also related to the legality of keeping the species; see post #45), but it was interesting to hear that they supposedly bred. Does anyone have more info about that?
I might feel tempted adding that the very high-level protection of this iguana is primarily based on politics, not facts on the ground, as it remains extremely common locally and the primary threat -the only that theoretically could cause its extinction- is related to global warming. It's the same with the Galapagos penguin and a number of other aquatic species restricted to this archipelago.
Unlike Fiji iguanas, earless monitor, certain New Zealand geckos, etc, where collection for the wildlife trade, if allowed to reign free, potentially could cause an extinction (though it appears the earless monitor is less rare than formerly believed).
The marine iguana and earless monitor are both quite high profile species and extremely few zoos have kept them, but then there are things like splashback poison frog of Brazil, Marañón poison frog of Peru and a range of Australian reptiles (where only the most widespread left the country legally decades ago, almost everything else originates as smuggled). The splashbag and Marañón poison frogs are currently kept in lots of zoos in Europe and are widespread among private keepers too, with many breeding it. All originate from smuggling that happened a decade or more ago (although some smuggling of unusual morphs of the splashbag apparently continues at low levels). There are several other examples; the marine iguana and earless monitor are far from alone.