There are lots of reasons why you may want to have copepods in your aquarium. Maybe you want to feed a
mandarin dragonet. Maybe you want the copepods to feed
corals. Maybe you need help with detritus control. Maybe its several different reasons, but whatever it is, you want to keep copepods to the best of your ability. You want more copepods because more copepods is always better. The more copepods you have, the more food will be available to your fish and corals. More
copepods also mean less detritus and even less algae. In order to maintain a stable population of copepods, you will need to provide some conditions. Here, you will learn what copepods eat and how you can feed them. You will also find information on how to maintain a steady copepod population.
Now, to get down to the good stuff!
Let's start with the initial question: What do you feed copepods in a refugium? Well, you certainly don't need to feed them pellets or anything like that. Most of the time, you don't have to feed your copepods at all! Copepods will find food in your aquarium on their own. Just as you want them to, they will consume detritus and algae. However, you can boost your copepod population by dosing
phytoplankton to your aquarium. Phytoplankton is needed for juvenile copepods. Dosing phytoplankton will not discourage your copepods from eating algae and detritus. In fact, they will eat it more because there will be more copepods to eat the detritus and algae. Dosing phytoplankton is essential for feeding copepods; more phytoplankton means more juveniles which means more copepods. The great thing about phytoplankton is it too will help feed your corals along with keeping the nutrient levels down.
So that's the feeding side of things. Providing your copepods food is important, but providing them a haven is even more important, especially if you have a mandarin dragonet. A single mandarin dragonet can easily eat thousands of copepods in one day. If you rely only on the population of copepods in your display, your mandarin may go hungry eventually, depending on how large your tank is, of course. One option is to add copepods to your tank a couple of times per month, but this can become expensive and unideal. Although it is certainly something you can do, a better route is to set up a refugium. You probably already know what this is, but in case you don't, it is a small tank or section of a filtration system that provides a place for you to grow things in a different environment from the display. Often times refugiums have substrate or media along with macroalgae and, of course, copepods. A refugium will offer a place for copepods to breed and live without getting eaten. They will make their way into the display little by little, ensuring that there are always copepods in your aquarium.
There are a lot of ways you can implement a refugium into your aquarium. It may sound intimidating if you are a new hobbyist, but worry not. It's easy!
The most common way hobbyists add refugiums to their system is by using a section of the sump as a refugium. All you have to do is pick a section of your sump and dedicate it to being a refugium, add some media, macroalgae, and a light and you're good to go! The only thing is which section should you choose? Preferably, you want your refugium to be the last part of your filtration. This will ensure that copepods can easily find their way into the display. It will also make the macroalgae remove nutrients more efficiently and make your skimmer work more efficiently as well. However, if you cannot make your refugium the last section (before the return section), having a refugium in a less ideal section is far better than not having one at all.
Another method of adding a refugium is by adding a whole separate tank connected to the main tank. This is more common on larger systems, but can be implemented in any aquarium system. This can even be done in a nano aquarium, though it is highly uncommon.
Speaking of nano aquariums, let's talk about hang-on-the-back (HOB) refugiums. HOB refugiums work the same way other HOB equipment works. A pump will pull water from the tank and into a box hanging on the back of the tank. Then, the water will flow out of the box on the other side and back into the tank. This option is most common for tanks without sumps, which is often nano aquariums. HOB refugiums can be super simple and relatively inexpensive, or they can be more complex and expensive.
Regardless of which of these options you decide to use on your tank, they all offer a place for copepods to live without getting eaten and will all help you maintain a stable copepod population.
If you want an easy way to get both copepods and phytoplankton, checkout these
combo packs.