Yes it is possible, just a case of Simple genetics. Any fish can be shown as a normal (endler in this case) thats their phenotype, in other words, what they look like. For example, "N" represents your normal (dominant) color, while "n" is a (recessive) albino. So you fish can be NN- pure normal or homozygous normal. But, they can have the recessive gene (heterozygous) for the albino trait which looks like Nn. These heterozygous fish look like a normal endler with normal color, but are hiding the albino gene. Or, in a pure strain of albinos, the fish would be nn, as they are only able to produce recessive albinos- therefore, they are homozygous albinos. Now, All you need is a momma thats Het. for albino (meaning they look normal but are hiding the albino gene) and a dad thats het. for albino, though both look normal, and those to hets make a recessive baby! Since albino is recessive, you need two copies, one from each parent, to make an albino baby which is nn. So yes, it is possible.
trevor