My first thought would be sperm retention too but then came across this, which makes sense:
I will try to make this simple and still explain things.
first, regarding two incompatible albinos crossing.
A phenotype, the visible trait, is albino however they have differant genotypes, the part of their genetic make up that has a mutation which makes them albino.
Also, each animal has two sets of genes, one from each parent. In order to get an Albino you need the parents to carry the albino genotype wether it is expressed in the phenotype or not (homoxygous and heterozygous), and the albino genotype they carry must be the same. The albino is the offspring that recieved that gene type from both parents, if it recieved one from one parent and a normal gene from the other it would appear normal, that is dominant over albino, and heterozygous for albino, carrying the gene but not expressing it.
when you cross two ressesive traits incompatible with each other the offspring look normal but are hets for both kinds, why do they look normal?
They look normal because they recieve one genotype from each parent, and nothing affects the phenotype, the reason they are normal is because the parents, althought they had a pair of genes the same still carried the normal gene, it was just masked.
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Tosha 
8.10.0 Ball Python (Harry and Fluffy and currently un-named)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Dessert Tortoise (Pope)
7.9.5 Fish (1,2,3,4...)
0.0.1 Frog rescued from pool skimmer
0.0.2 Lizards rescued from pool skimmer