Corydoras Look-a-Likes = The Black
|Allan James: ( www.scotcat.com)|
Terms of Reference:
his is an investigation on the diversity of body shape and colour markings on the small South American tropical catfish genus, Corydoras.
My personal observation is of a total of 28 corydoras species from the so-far discovered 130 species plus in the wild. My first set of articles begins with the so called Black Striped Corydoras types then on to the Spotted Cory's and lastly on to the Any Other Varieties. I have started this series with the former. These articles are based on my 22 years personal experience (1983) of keeping, observing and breeding of more than 50 species of Corydoras catfish.
The Black Striped Corydoras.
I begin with the so called, black striped Cory's which includes Corydoras adolfoi, duplicarous, arcuatus, narcissus, axelrodi, loxozonus, davidsandsi and melini. First of all we have adolfoi from the tributaries of the Rio Negro in Brazil and the look-a-like C. duplicareus from the same river system, but further north. Both species have a light silver-grey body colour with a black band which bridges over the top of the head, extending over and below both eyes. A black band runs on the top of the body from the front of the dorsal to the beginning of the caudal peduncle. They both have an intense golden yellow to orange to the top of the head which is called the supraoccipial. The difference between this pair is that duplicarous has a broader black band running on the top of the body, further more this band can sometimes reach all the way down to the lateral line.
Corydoras arcuatus is found in Peru and just over the border from the River Napo system in Ecuador. This fish is similar to Corydoras narcissus from the tributaries of the Rio Purus in Brazil. They both have a wide black band, on a silver grey body colouration, that runs from the snout, through the eye and over the top of the body and ending on the lower edge of the caudal fin. The marked difference is that narcissus has a longer snout and the black band in some specimens, indistinguishable from the snout to the beginning of the eye.
Corydoras axelrodi and C. loxozonus both come from Colombia with the former in the Rio Manacaacias, a tributary of the Rio Meta and the later from the Cano Limon, a tributary of the Rio Ariari. The difference in this pair is that axelrodi has a main black body stripe through the lateral line from the head to the caudal fin while loxozonus has the stripe higher up on the body, running from the start of the dorsal fin to the caudal fin. There are further peculiarities, but this is the main one for identification purposes.
There are subtle differences between Corydoras davidsandsi and Corydoras melini which tells them apart, the main criteria being the position of the black band that runs along the top of the body from the start of the dorsal fin, with davidsandsi having it running along the ridge of the back, around the adipose fin, and ending on the lower tip of the caudal fin.
Corydoras melini also has this band, but, it splits into two and runs further down the body and ends at the tip of the caudal fin. In other words, melini shows the body colouration on the top of the body when you look down on them from above, and davidsandsi shows the single black band over the top of the body from above. the Rio Negro in Brazil while melini can be found a considerable distance away in Colombia,Ecuador and Brazil, in the Amazon near the town of Benjamin Constant.