Australian Red-claw Crayfish (Cherax quadricarinatus) Tampines Quarry Lake, 10th September 2012
This exoskeleton of an Australian Red-claw Crayfish was found on the shore of Tampines Quarry Lake, an artificial lake that formed out of a disused sand quarry. Hence most of the larger aquatic fauna like fishes and decapod crustaceans are likely to have been introduced by humans. The presence of a crayfish exoskeleton suggests that there might be a population living in the lake, although I have yet to see a living specimen.
Discus (Symphysodon sp.) Potong Pasir, 7th March 2012
This dead discus, a South American cichlid native to the Amazon Basin, was seen at the foot of an apartment block by Alvin Lim, who took a photo and shared it on Instagram.
There was no water nearby, and my guess is that this was not an abandoned pet. It’s possible that this was a case of a fish jumping out of a tank placed close to a window, only to end up falling all the way to the foot of the block. Alternatively, the fish could have died in the aquarium, only to be dumped out of the window instead of being tossed into the trash or flushed down the toilet bowl.
It is also possible that this discus fish had been released into a nearby canal or pond, only to get snatched and subsequently dropped by a piscivorous bird like a kingfisher, heron, or raptor. We probably won’t know for sure.
The vast majority of discus seen in aquariums are captive-bred varieties that have undergone intensive artificial selection for distinctive colours and patterns. The taxonomy of discus in the wild is still unclear, but most traditional references list 2 species; consequently, the nomenclature regarding domestic varieties (some of which might be hybrids between discus belonging to different populations or even species) also requires further clarification.