Yellow pineapple VT male
Cellophane VT female

Neither has any red (other than visible blood supply.. thin skinned)or blue.
Male has the black outline of scales of a pineapple.

Cello is tricky. The thing about cello is that it is not a color, it is an absense of color. This is the whole phenotype and genotype thing.
Forgive me if you know this, but I am repeating for those that don't
When you talk about phenotype, you are talking about what the fish looks like. I find it easier to think PHOTO-type. You are seeing some of the gentics of the fish, but only those that are expressing themselves, or showing, to put it simpler.
Then there is the genotype. The genotype is the genes that the fish carries, including the ones you can't see, or recessives.
This is why you hear sometimes HM geno, or DT geno. They carry the genes, but they do not express them.
A cello fish is expressing an extreme form of marble, where the marble gene has caused the actual color of the fish to transpose into a lack of color. A cello fish while phenotypically has no color, may genotypically be any color.
Because we don't know what color she actually is, the only thing that can be said for sure is that you will get VTs, and you will get marbles.

Now depending on what genes they BOTH carry, it is possible to get DTs and PKs, if they should carry those genes. And with DT, sometimes it is not apparent that the fish is carrying it, they don't express the DT geno dorsal.
Colorwise, aside from marble, you could get anything. Multis are highly likely. If the female is carrying NR1 (yellow), you could get yellows from that pairing. If not, then reds are likely, even the male is not showing red, he is genetically a red fish.. (that phenotype, and genotype thing again).

Haha! My brain hurts.
Well, is there a way to get more cellos? Or are they actually considered something that is undesirable?
She is tooo pretty and very graceful.
Her name is Apparition.
;)

I like cellos, lol.
I don't know that you can consistantly produce cellos, but as Ruth noted, the more she bred her marbles together, the more cellos that seemed to be produced.
I am getting a fair number of cellos from my marbles as well.

It is not that they are undesirable, there is a show class for them. The thing is, it is hard to get good cellos, because they should be irrids free, and most of them have the irrids sheen on their fins.

cellos are cool, just kinda hard to predict lol.

Now, gotta warn you, Belle said it, but I'm saying it again, yellow is a form of red as expressed by the NonRed1 gene. Unless the female ALSO carries NR1 you're going to get babies with red. Just something to keep in mind.

The biggest catch when breeding petstore VT's is that you have no way to predict their genes till you see what babies they produce. Honestly you could get a huge range of colors.

I'll pass on this combo then..
They are just too pretty, but I'm starting to realize that 2 pretty fish can beget really ugly babies.