There is at least one colorational variant of "C." umbriferum, the so-called green cichlid, which may well be another distinct species. According to Konings (1989), the German aquarists Heiko Bleher and Hans Mayland discovered in 1983 a "large green cichlid" in Gatun Lake (Panama, an artificial impoundment lake west of the canal), that he describes as a "primitive predator." According to the American aquarist Dan Fromm (1989), this is, in fact, "C." umbriferum, which he and Dale Weber collected in 1983 from the Tuyra-Chucunaque drainage of Panama, farther east of the canal. Eigenmann (1924) indeed records the distribution of "C." umbriferum as including the Tuyra and Chepo basins of Panama.
Photos of this fish, caught by Bleher and Mayland in the Rio Sambu, can be found in Bleher's (1989) two-part account of a collecting trip to the Darien of Panama. He describes it thusly: "...we caught a 55-centimeter (22-inch) 'monster,' the largest I had ever seen. The natives explained that they had caught even larger specimens. This blood-red-chested green devil (what we called it) had unusually large teeth. An irregular black line began behind the posterior end of the dorsal fin. Covered by remarkable iridescent-white spots and being overall army-green colored, it had a power that was matched only by the crocodile! I collected a pair and carried the monsters just don't ask me what it took to keep them alive..."
Photos of the "green cichlid" appear also in Stawikowski and Werner (1988) on page 84. Jeff Rapps believes he has a young pair of the green cichlid I have seen them and they certainly don't look like the typical "umbis," but only grow-out to adulthood will tell.