Hi,
With the exception of cobalt and black, most of Janků's "Ryby" series appear in these colours, as well as cased examples, such as crystal over virginit, oceanit over virginit, and so on. There may be some examples in cobalt and black, but never having seen one, I cannot confirm or deny with any certainty. Others such as dogs are seen in cobalt, and later, animals in cobalt with crystal highlights. These last are probably after 1989. There exist also, some Janků figures with "marvered-in" colouring.
M