Zebrafish as increasing being used as it means use of less animals in research. The larval forms are transparent so you see things you can label structures with green fluorescence protein from Jellyfish or mCherry a monomeric red fluorescent protein from disc coral.
This study has devised a novel way to demyelinate axons by having an oligodendrocyte toxin that can be switched on and off. As is common in mammals the default pathway is rapid repair. This system may be used to study repair.
It is a shame that many drugs that get into the brain are like brick dust when it comes to dissolving in water, but maybe there is space for a new FishDoctor on the blog?