Pseudomugils will take dry food fine, but I also recommend breeding this species as they are relatively short lived. Sometimes dry foods aren't enough to produce a lot of eggs. This is what I generally feed pseudomugils:
Live baby brine shrimp will make your life super easy with luminatus and many other pseudomugils.
If you are unable to provide this regularly, frozen micro crustaceans are readily accepted: baby brine, daphnia, cyclops, copepods, etc. You can also use a cheese grater (use caution) to grind down larger frozen foods such as brine shrimp or bloodworms.
In terms of dry food, recently I've really liked Agcore Ommnivore Crumble Bits (0.5-1mm).