I can't think of the latin names, but there's two species of African tetra, I believe usually called tiger tetras, that are similar to what you described. Very Leporinus looking.
Any fish in the headstander family are aggressive. Loves to nips fins!
They are the only easy to get fish that swims at a major slant angle, I believe. To find this pic, All I did was go to www.google.com, press the "search Images" and type in "Headstander". Im sure typing in the scientific name would get more results on this fish. With just the word headstander, I got a guy standing on his head!
dbcb314
There are many different Variations of this type of fish...