Other species familiar in the aquarium trade are : the black ghost knifefish ( Apteronotus albifrons ) , the glass knifefish ( Eigenmannia virescens ) , and the banded knifefish Gymnotus carapo . A few species are familiar to the aquarium trade , such as the black ghost knifefish ( Apteronotus albifrons ) , the glass knifefish ( Eigenmannia virescens ) , and the banded knifefish ( Gymnotus carapo ) .