The Red-tailed Black Shark, also called Red-tailed/Redtail Black Sharkminnow, is not a shark but is named after its torpedo-shaped body and high, triangular dorsal fin. It belongs to the carp family and is endemic to Thailand.

It grows to some 16cm (6 inches) long. It is critically endangered, although not uncommon in aquaria. From 1996 to 2011 it was thought to be extinct in the wild, mainly through construction of dams and draining of swamps in the 1970s. Aquarium fish are captive bred.

The Rainbow Shark/Sharkminnow, also called the Red-finned/Redfin Shark(minnow), is not a shark but is named after its torpedo-shaped body and high, triangular dorsal fin.

Similar to the Red-tailed Black Shark, it has red fins as well as a red tail. It belongs to the carp family and is native to southeast Asia. It grows to 15cm long.