Zebra Danio's are dyed sometimes. It's against the law here in the UK, but they are allowed in some parts of the US.
They are known as 'Glofish'
That's just one examle.
Thats not true. The "Glofish" are genetically altered. The embryos of the great-great-great-grandparents of the glofish that you see in the store were spliced with the genes of organism that glows naturally. The color in glowfish is from a natural, fluorescent protein rather than a dye. The fish are born colored. Not to say there aren't dyed zebra danios, but Glofish are not dyed. The Glofish company has even copyrighted the genetic sequence of the fish, so only one company can make these fish. They are banned in the UK because they are genetically modified animals.
The fish I've seen dyed before are usually white blood parrot cichlids and I've even seen an albino corydora with blue dye injected into the base of its tail. Fish that are naturally see-through or white are the usual targets.
