Pterophyllum species

Let me first state that this won't be as comprehensive nor can I claim any expertise on the subject matter. But like any serious hobbyist, I am eager to learn more about the hobby and simplifying what I have known or read so that others can understand more of the fish, the issues and even controversies involved.

Science like any other aspects of the real world, is as confusing with the amount of knowledge available (especially through the internet) as there are different school of thoughts on a certain subject or issue. What is really important to understand are the basics of science - science in effect is a means, to understanding and trying to disprove what previously have been well-accepted and even proven. As we go further, a theory in essence is only as good as long as it isn't disproved or replaced with a new one.

How many species are there within the genus Pterophyllum? Answer is simple, depends on whom you listen to or read from. Generally atleast, it is widely accepted that there are three known species, namely scalare, leopoldi and altum. others claim that there are indeed only two, scalare and leopoldi with the altum as a subspecie of the scalare. Thus, P. scalare scalare and P. scalare altum. This is based on the fact that scientists follow several criteria for defining a species. The following are a few of the criterion (thanks to B. Bolival for sharing them):


Typological Species Concept wherein a species is a group of organisms that share a unique set of diagnostic morphological characters that make that group different from all other species.

Biological Species Concept concerns itself with species as a cohesive natural group of interbreeding individuals that are isolated from all other groups (isolated gene pools).

And Recognition Species Concept which states that a species is a group of organisms that recognize and breed only with each other in the wild - it is unimportant what they can and will do so in an artificial no-choice situations in captivity.

To be continued.....