Like many tank invaders, Cyclops can be very hard to get rid of once you have them, even if you take drastic measures, like a complete tank tear down.
Thankfully, since cyclops are predators, you can control them by taking away their food source. They feed on microscopic protozoa, which in turn feed on detritus in the tank.
To get started, I would recommend you remove all the plants from the tank and sanitize and quarantine them for a minimum of 2 weeks. A plastic shoe box with some clean, treated, aged water is perfect for this.
Next, you will need to change your tank maintenance routine a bit. If you are using a substrate, siphon this often. Try to get every bit of leftover food and animal waste out. Do not siphon out a lot at one time, just enough to get the gravel as clean as possible. Purchase an algae scrubber, if you do not already have one, and keep the algae off the sides of the tank.
Reduce lighting to only a few hours a day.This will keep the algae and photosynthetic organisms at bay, thereby starving out the predators like cyclops. After a week you will notice a decrease in numbers.
Make sure you change your filters regularly too, and keep the filter pump clean and free of sludge. Give any tank decorations a good scrubbing with a stiff bristled brush under hot tap water and allow them to air dry.
Keep checking on your plants daily, looking for signs of infestation. If you see any, resanitize the plants and start the quarantine session over. Once the plants have been critter free for at least a week, they are ready to be replaced in the tank.
