Can I Put Fish in My Refugium?

Can I Put Fish in My Refugium?

So you’ve got a big, healthy refugium attached to your main tank. Just sitting there, without much movement in it (well, aside from thousands of little scurrying pods). Especially if your main tank is chock full of fish, you might start to wonder: Could you keep more fish down in the fuge?

The best answer to start with is yes, maybe.

What’s the big reason for wanting to put fish in there in the first place? If it’s because there is no more room in the main tank, then you might want to opt out--the bioload might already be too high to add yet more fish!

If you want to add fish just to “spice up” the fuge--add movement--remember that this is not a place for active reef fish. Not only are refugia a bit smaller than the main tank (though they don’t have to be!), they also are often densely planted with macroalgae. This means that, for the most part, only small fish will “fit” in there comfortably. However, it’s usually the smaller fishes that are the most voracious pod eaters. In other words, putting such a fish where your pods are concentrated could spell the end of a self-sustaining pod population. Similarly, an herbivorous fish could wipe out all of your macros in short time.

So what could go in the fuge? Smallish, relatively inactive carnivorous (non-pod eating) fishes might work. For example, a frogfish or dwarf lionfish might be great there (especially because they likely could not go in your main tank). A clingfish, hawkfish or Bangaii cardinalfish might work as well!

The important things to consider here is (1) whether or not the fuge environment provides the right type/amount of living space and (2) whether or not the fish could deplete the pod or macro population!

Those outside the hobby may not see refugiums as anything special, but hobbyists often take a lot of pride in their refugiums, as they should! Refugiums are often an essential part of a reef aquarium, serving the tank in several different ways. Fish may not be the best way to spice up your refugium, depending on the size. If you have a small refugium, worry not! There are a few other ways you can make your refugium more interesting without adding fish. 

One way to add some flavor to your refugium is with inverts. Inverts are often overlooked in the saltwater aquarium hobby. They are often seen as nothing more than clean-up-crew members, which of course they are perfect for. However, there is still some underappreciated intrigue to inverts such as crabs, shrimp, snails, and urchins. You could also add a starfish to your refugium or an interesting shrimp. It can even be a good opportunity to add an invert that would otherwise cause problems in the display. As with the fish, don't add anything that could diminish the primary purpose of the refugium (macroalgae growth, copepods, etc.). 

Another way to do a little something extra with your fuge is collect different kinds of macroalgae. Generally, Chaeto, Sea Lettuce, and other green macroalga are best for nutrient export. However, there are other macroalga that have more interesting, even beautiful looks. Keep in mind that this macroalgae is still excellent for nutrient export. For example, you could add some Dragon's Tongue macroalgae, which is interesting because of its flame like ends. Furthermore, Blue Hypnea is fun because of its blue coloration, typically not seen in macroalgae. There are hobbyists who have aquariums dedicated to macroalgae, so it certainly makes sense that having a small (or large) collection would make your refugium more interesting!

Whether you decide to add fish to your refugium or take a different route to add flair, taking interest in the different parts of an aquarium rather than just the display is something you should feel proud of. It makes our beautiful hobby more rewarding and more fun. Remember, what you do with your tank is ultimately up to you, but use the advice given here to steer you in the right direction. 

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