I am new to aquarium fish. Could anyone help me identify these species? I found it in local aquarium store in Chengdu, China, where I am visiting.
It is about 6 inches long, it has a black body with a couple of white stripes on the tail. It has a very long wavy fin on the bottom and can easily rotate in water as well as swim upside down.
Thanks in advance for advice or resources to use in case of finding unknown fish species.