3 Functional Fishes for a Reef Aquarium

Most of the time, I buy saltwater fish for my reef aquarium because I think the fish is cool, fun to look at something inside me just says, I simply must have it. Are you like that? Well, some fish are cool, fun to look at AND will work…for free. I call these fishes the functional fish for a reef aquarium.

3 Functional Fishes for a Reef Aquarium

So what turns an ordinary fish into a functional fish? If an awesome, reef-safe fish has a natural behavior that improves the conditions of the tank, I consider that to be a functional fish.

There are (at least) three categories of functional fish:

  • Cleaners
  • Algae eaters
  • Pest removers


Cleaner fishes, provide two benefits to the average marine aquarium. The most obvious benefit is that cleaner fish will eat and remove parasites from the other fish in your reef aquarium. These little guys are no match for a serious infestation of saltwater ich, but they can help be an insurance policy against a bad outbreak.

neon goby a functional fish

In addition to picking off and eating any trouble makers, cleaner fish have also been shown to reduce the amount of aggression displayed between fish in a captive setting. That’s right, when cleaner fish set up ‘shop’ in your tank, they more they clean, the less aggressive the other fish are prone to be.

These small fish pack a lot of personality, are fun to watch and provide some pretty significant functional benefits to your tank.

Algae eaters

Every one of us, in this hobby, works pretty hard to keep problem algae under control. Let’s face it, our aquaria would actually be just tanks of algae, bacteria and cyano and dinoflagellates if we let it get ugly. Why not stack the deck a little bit in your favor by having a fish or two that will help keep the algae in check.

yellow tang

Tangs, rabbitfishes and blennies are all solid algae eaters and will help you keep one step ahead of the algae.


Pest removers

Got aiptasia? Don’t blast them away with chemicals, consider keeping them at bay with an aiptasia-eating Copperband butterflyfish.


Do you have unattractive flatworms in your tank? Some wrasses, like the six line and melanurus wrasses, are known to eat flatworms and can help you keep the population under control.

Two quick disclaimers:

  1. Adding one of these functional fishes to your aquarium is no substitute for good husbandry practices. You should still practice good quarantine protocols, to help keep parasites from getting into your tank. You also shouldn’t let algae get to out-of-control levels in your tank and just hope for the best with your algae-eating fishy friends. But if you are on the market looking for a new fishy addition to your reef tank, why not consider one of these awesome fish that will also get some work done in your tank for you.
  2. Also note that two of the fishes mentioned here (cleaner wrasse and Copperband butterflyfish) are delicate creatures with specialized dietary needs and should not be purchased ‘on a whim’. Please take the time to research there needs before adding them to your reef to ensure a positive outcome.

More Information

Here are a few other posts you will enjoy reading:

Great beginner fish for a saltwater aquarium

5 starter fish to avoid

Your comments

I left out a few functional fishes for the reef aquarium. What are they? Leave a comment below.


  1. I’m putting a fish tank in my room, so knowing what fish I should get will help me have a decent collection of fish in my new tank. I like your suggestion to put fish that are pest removers in my tank. It seems like having fish that would eat flatworms in my tank like the melanurus would be really useful. I’ll make sure I have a few pest removers in my tank. Thanks for the post!

  2. I know this article was about functional fish, but sometimes invertebrates can be even better at some of these functions. Especially for cleaners, cleaner shrimp are much easier to keep that say a cleaner wrasse. Although, a neon goby qualifies as a cleaner fish as well and are more suited for a cleaner wrasse. Overall great article though!

    1. Author

      Hi Eric B,

      Thanks for the comment. I do agree with you, some of the invertebrates are extremely functional. Perhaps that would be a great article to complement this one. What invertebrates do you recommend?

  3. I’d definitely recommend skunk cleaner shrimp as cleaners, maybe blood red fire shrimp as well. For eating algae I like using trocus snails and Scarlet red hermits. And for pest control, I only know of peppermint shrimp for aipasia anemones. I know some nudibranch’s specialize in eating flatworms but aren’t really suited for home aquariums. It would definitely make an interesting follow up article in my opinion.

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