Fix is a reducing agent, which in chemical terms means that it moves oxidized metals closer to their metallic state -- this is what is does in photo processing -- causes the unused silver salt in an emulsion to reduce to a different silver compound that is contained in the spent fixer. (Which is why dumping used fix down the drain is very uncool -- dissolved silver is not removed at the sewerage treatment plant and escapes into the environment and acts like any other heavy metal contaminate, e.g. mercury.) In this case, the fix has done the same to the selenium in the toner, causing it to fall out of solution.
In any case, both solutions are toast and should be disposed of (in a responsible manner, of course...)