Sometimes a question just gets in my head and I have to have an answer. The latest occurrence of this is related to Albino Oscars and Lutino Oscars. What are they? This led to many hours of researching numerous articles on the Internet and I came to a single conclusion. No one, even in science, has a definitive answer. Of course, science understands albinism. We can readily identify a true Albino Oscar by an absence of dark coloration and red eyes, but what makes an albino an albino? And what is a Lutino Oscar? Is it a form of partial albinism? Is it an example of leucism? Or is it something else.
This is where there are differing opinions and there are no absolute answers. Because the answers are not written in black and white (at least not where I've been able to find them), we are left to draw conclusions, which is what this article is all about.
So let’s delve into the differences and questions. Science has definitive definitions of what constitutes albinism and leucism. Both have defined physical characteristics, at the cellular level, resulting in the physical characteristics we see.
Albinism is the result of a genetic dysfunction/mutation that prevents the production of melanin pigment. Melanin is responsible for all dark coloration. In a human, freckles are an example of concentrated melanin pigmentation. The darker a humans skin, the more melanin pigment it contains. The same is true for fish. A good example of a fish, which has been selectively breed for enhanced melanin pigmentation, would be Black Lace Angelfish. An absence of melanin means that the affected animal (in our case, fish) will have no black, brown, grey, or green coloration. However, other types of pigment cells, such as carotenoids (reds, oranges) and xanthophores (yellow), are unaffected. This means that an Albino Oscar can retain its natural orange and red coloration, loosing only the darker colors.
Leucism is the result of a genetic dysfunction/mutation that results in a reduction of all skin pigment, not just melanin. In nature, this generally results in an all white animal and the only confirmed instances of leucistic fish I have found (thus far) demonstrate exactly that, all white fish. In nature, it is not uncommon for animals to display irregular patches of skin that are leucistic, resulting in what is known as a “pied” (or “piebald”) effect. However, I have never seen a “pied” Oscar (but I have seen “pied” convicts). It is my belief that a Leucistic Oscar would be all white, with normal eye coloration. Eye coloration is unaffected in leucistic animals because the pigment cells that determine eye color are unaffected by the genetic cause of leucism.
Based upon the above definitions we can safely identify that Albino and Leucistic Oscars are two totally different animals, each affected by a physically different genetic disorder. We can also draw our first conclusion, that Lutino Oscars are not leucistic nor are they a partial form of albinism. A leucistic oscar, unless it can be traced back to the “piebald effect”, simply would not be capable of producing the dark coloration on the outer edges of the fins that is somewhat characteristic of a Lutino Oscar. But it is not realistic to attribute the dark fins to the piebald effect as such an animal would have splotches of normal coloration on other areas of its body. Nor can it be attributed to the same leucistic mechamism that results in normal eye coloration because the eyes being unaffected (by the genetic cause of leucism) is unique to the origins of retinal pigmentation cells. Nor would it be probable that a Leucistic Oscar would possess bright orange or red colorations. This is much more likely in an albino than in a leucistic. The few examples I’ve found of non-pied leucistc animals that display coloration involve very muted and limited colors, as in the below examples:
So, what about Lutino Oscars? If they are not albinos and they are not leucistic, what are they? It is my belief that Lutino Oscars are a color morph and NOT the result of a genetic dysfunction/mutation. I believe that Lutino Oscars are the result of selective breeding of fish with an abnormally high percentage of leucophore pigment cells, which results in white pigmentation, or fish that have been selectively breed to remove black pigment cells (melanophores). This should not be confused with an absence of pigmentation (as exists with albinism or leucism). Unlike albinos and leucistics, these fish retain fully functional pigmentation. It’s just that their pigmentation is predominately white. We know that Oscars possess leucophore pigment cells because one of their natural colors (in the wild type) is green. Green coloration is achieved when melanophores are juxtaposed with leucophores. Reduce or eliminate the melanophores, through selective breeding, and you are left with a white fish. This could also explain where the name “Lutino” comes from, as the dominant coloration (white) is a result of LEUcophores.
Finally, we have an oddity of the Oscar world, the Lemon Oscar. Judging by eye coloration, Lemon Oscars are not Albinos. They are possibly a result of xanthochromism, a genetic condition where red pigments are replaced with yellow. So Lemon Oscars would actually be Xanthochromistic Red Oscars.
To help with identification, the below information is provided:
Albino Oscars will be pale white, retaining orange and red coloration (potentially vivid), possessing no dark (black, brown, green, gray) coloration. Eyes will be red or pink. Many people purchase what they think is an Albino Oscar but if the fish is displaying any dark (black brown, green, or grey) coloration, it is not an Albino Oscar.
Leucistic Oscars are likely all white, and will have normal eye coloration. Leucistic Oscars are exceedingly rare. It is possible for a Leucistic Oscar to be partially white, with irregular splotches of normal coloration. But these “splotches” would be more than the orange and red colors we normally attribute to Albino or Lutino Oscars, including the darker colors normal for Oscars. While I have never witnessed the pibald effect in an Oscar, I am aware of its existence in convicts, Angelfish, and other cichlids. It is also possible for a Leucistic Oscar to retain very faded orange and red coloration.
Leucistic Oscars will not be capable of developing vivid orange or red coloration.
White, can retain (potentially vivid) red, orange, and dark colorations. Will (usually) have normal eye coloration and usually has black edges to the fins.
A Red Oscar where the red has been replaced with yellow. Regardless, this is neither an Albino (based upon eye color) nor a Leucistic (yellow is a pigment). Its actual definition would be a Xanthochromistic Red Oscar.