Tank has been going for about 4 weeks now. A 29 gallon Oceanic Bio Cube. Are copepods and amphipods something that I should see majically appear one day and how long does it take for that to happen?
They need to hitchhiked with the sand/rock, otherwise, you won't see them. Rather they will increase to significant number depends on the availability of food, and how much predation there are in the tank.