CAUTION! 10 Popular Animals That May Not Be Reef Safe (2023)

CAUTION! 10 Popular Animals That May Not Be Reef Safe (1)

As a reef aquarium owner, you invest a great deal of time and money in making sure your aquarium looks good and your animals are happy and healthy.

The last thing you need is a new fish or invertebrate that can hurt or kill your other aquarium inhabitants!

Today we're going to look at some of the most popular but controversial species available in the marine aquarium trade to help determine which specimens are right for your reef aquarium.

We share which animals might and might not make good aquarium mates in a mixed reef and explain why.

CAUTION! 10 Popular Animals That May Not Be Reef Safe (2)
Photo credit:Photo credit: National Marine Protected Areasnbsp;National Marine Protected Areas


This family of fish is arguably one of the most colorful and exquisite of all saltwater fish. Unfortunately, many butterfly fish are not reef safe and are true coral feeders (meaning they only eat coral polyps).

Furthermore, many of them, even those considered "reef safe", are not always the most resilient and should only be left to the "experts".

Potentially Reef Safe:Pyramid Butterfly(Hemitaurichthys polylepis),Zoster butterfly(Hemitaurichthys zoster)and the Copperbanded Butterfly(Chelmon Rostratus).

Generally available but not reef safe:Raccoon Butterfly(Chaetodontidae lunula),Auriga butterfly(Chaetodontidae auriga)and Marine Depot's mascot, the Double Saddle Butterflyfish(Chaetodontidae ulietensis).

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Photo credit: Leo Chen


If you've ever seen a triggerfish swim, you've probably been amazed by their sheer beauty and elegance. It's almost as if they are gliding through the water, propelled by their elongated dorsal and anal fins. Triggers come in a variety of colors with some very intriguing color patterns.

Unfortunately, most of these fish are not safe for a reef tank. They are predators and can make short work of your invertebrates along with smaller and/or more docile fish.

Potentially Reef Safe:Niger-Trigger(Odonus niger),Blue neck trigger(Xanthichthys auromarginatus),Crosshatch trigger(Xanthichthys mento).

Generally available but not reef safe:They are triggers(Rhinecanthus aculeatus), Clown-Trigger(Balistoides spike)and wavy trigger(Balistapus undulatus).

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While this may be a bita controversial topicI personally feel that seahorses should not be placed in most reef aquariums, especially SPS dominated aquariums. In general, the high flow required for SPS aquariums does not bode well for the seahorses.

Seahorses also need "hitching posts" to hold on to, and will wrap their tails around almost anything to keep themselves in place. This can harm some corals or the seahorses themselves (by being stung by corals).

If you have set a goal to get a seahorse in areef tank, you should first build the roommates around the needs of the seahorses. Corals that don't sting or compete for food are your best choices, like leather corals or sea fans.

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Photo credit:Credit: Mike Poreskynbsp;Mike Poresky


When it comes to angelfish, they generally fall into two distinct categories: Dwarf angels(Zentropyge)and "big" angels(Pomacanthus, Genicanthus, Apolemicthysand a few others). In these two groups you will find some of the most colorful saltwater fish in existence. With bright reds, yellows, oranges and all blues... these fish are bursting with color!

The bad news is that some of the most colorful and stunning angelfish can wreak havoc on a reef tank. Even those considered "reef safe" may one day decide they like the taste of your most prized coral.

Potentially Reef Safe:Flame Angel(Centropyge loricula),Flameback-Engel(Centropyge Acanthops)and coral beauty(Centropyge bispinosa)Angels from the dwarf group and one of theGenicanthusAngels (Bellus, Lamarcks or Blackspot) or Regal Angel(Pygoplites diacanthus).

Generally available but not reef safe:From the dwarf category of the Lemonpeel Angel(Centropyge-Gelb)and bicolor angel(Centropyge bicolor);from the great angels, Flagfin Angel(Apolemichthys trimaculatus),Rock Beauty Angel(Holacanthus tricolor)and the majestic angel(Pomacanthus navarchus).

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Who doesn't love a puffer fish?

They have some of the most outgoing and fun personalities of any saltwater aquarium fish and have been known to interact with their owners through the walls of the tank.

As you might have guessed, puffer fish can make short work of many reef aquarium residents. Most puffers are therefore best suited to fish-only tanks.

However, there are some smaller puffers, sometimes called "tobies," that have the potential to live peacefully in a reef aquarium. Just make sure to choose their aquarium mates carefully and watch their water flow - too much water can be bad for them.

Potentially Reef Safe:Valentine Buffer(Canthigaster valentini)and blue spotted puffer (Canthigaster solandri).

Generally available but not reef safe:Dog Face Buffer(Arothron nigropunctatus)and porcupine puffer(Diodon holocanthus).

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Photo credit: Jerry


Wrasses are a huge family of fish that vary widely in size and color. However, most share a similar body shape: long and lean.

Many wrasses are very robust and make an excellent addition to a saltwater aquarium. Some strains will thrive on their own in a tank; others prefer to be in a group. Wrasses made our list because some are excellent predators that can cause problems when placed in a reef aquarium.

reef safe:Any fairy or blink wrasse(Cirrhilabrus sp. and Paracheilinus sp.),Mysterious wrasse(Pseudocheilinus ocellatus)and Leopard Wrasse(Macropharyngodon meleagris).

Generally available but not reef safe:Green Bird Wrasse(Gomphosus varius),Spoonfin Wrasse(Thalassoma lucasanum)and sunfish(Thalassoma lunare).

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Photo credit: Drow_male


One of the most beautiful fish, in my humble opinion, is found in the filefish family. With orange spots on a light green body, the Orange Spotted Filefish is a beauty!

There are many other species but none as colorful as the Orange Spotted Filefish which interestingly NEEDS a reef tank to survive as it feeds on acroporate tissue/polyps. Some hobbyists have been able to get them to eat processed foods, but this does not guarantee the fish will survive in captivity. There are other filefish that are suitable for aquarium life just not for life in a reef tank.

Potentially Reef Safe:Matted Filefish(Acreichthys tomentosus)

Generally available but not reef safe:Tassel Filefish(Chaetodermis penicilligerus)

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A reef aquarium seems to be the perfect environment for an anemone. With high intensitylightingand goodFloware required of both, they seem to be a match made in heaven.

However, an agile invertebrate laden with powerful, piercing tentacles can cause mass destruction in a tank. In addition, many anemones can grow quite large or even multiply and take up a lot of space in your aquarium.

My Rose Bubble Tip Anemones (RBTA) are perfect examples of this. I started with 3 anemones four years ago and now have over 20 anemones in my tank. I've also sold/traded well over 50 in that time. The RBTAs have stung/killed almost every other coral in my tank and are now dominating the tank.

In most cases I would advise against keeping an anemone in a mixed reef aquarium. A species-specific reef tank would be a more suitable home for anemones.

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Sea urchins are great scavengers. They eat all kinds of algae as well as meaty foods. Despite their size, they can penetrate small cracks/crevices in your rock to eliminate algae.

The bad news: Some people also like the taste of coral!

The Diadema Urchin (Long Spine Urchin) in particular likes to gnaw on SPS corals and coralline algae. I had several freshly glued SPS offshoots that were destroyed by my sea urchin. While many websites list these types as safe for reef aquariums, I would suggest proceeding with caution before putting one in your own tank.

reef safe:Blue Tux Brat(Mespilia globulus)and pincushion hedgehogs(Lytechinus variegatus).

Generally available but not reef safe:Pencil Urchin(Eucidaris tribuloides).

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Photo credit: Ne?l?


Starfish can be a great addition to a marine aquariumcleaning team, but not all starfish are beneficial to a reef aquarium. Many are omnivores, feeding on algae and leftover food in the tank, but others will prey on coral, clams, or even fish.

reef safe:brittle stars(Ophioderma sp)and brittle stars*(Ophiocoma sp).

Generally available but not reef safe:Green Brittle Stars(Ophiarachna incrassata)and Chocolate Chip Stars(Protoreaster nodosus).

*Brown/black or almost any color except green (see non-reef safe list).

While there are exceptions to every rule, hopefully the general guidelines in this article will help you avoid a potential disaster in your reef tank. Every reef keeper, every tank and its inhabitants are different - so while one hobbyist may be successful with a particular species, another may not.

The key, as I'm sure you've heard many times, is to do a thorough research on the livestock you intend to keep before you buy. Don't buy fish or inverts spontaneously - it's not worth the risk. There is a ton of information in books and on the internet to help you make informed decisions about your stocking needs (In addition, you can always ask us!).

Doing your homework before you buy will prepare you for any challenges that lie ahead and help you avoid irresponsible and potentially disastrous pet purchases.

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