List of marine fish that should not be kept in captivity.

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If It Won't Live in Aquaria, Leave It in the Ocean!
(The List)
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This is not a complete list by any means.
We will up-date this list from time-to-time. Please note that not all members of a listed Genus or Family are difficult to keep. Many species that are closely related to those listed here are hardy. If you disagree with any of our selections, or feel we've left out a particular species, please email us by clicking here. We'll evaluate your comments and revise our list if you can plead a good case. Comments like "I've kept one for years" will be ignored, as exceptions to everything in life and nature exist, and your case is the exception, whether you like it or not.

How Our List is Organized:
Fish species appear on our list for the following reasons:

Diet: Require a specialized diet, very difficult to duplicate in captivity.
Habitat: Require a specialized habitat which is very difficult to simulate.
Drugs: Often collected using Sodium Cyanide or drugs, or which come from areas of the world where these methods are still in use.
Aggressive: Extremely aggressive, have large territories in the wild, and are unsuitable for most community aquariums. Aggression in fish is not an indicator of "anger" but is due to highly-territorial behavior.
Dangerous: Fish and invertebrates that are able to poison or severely hurt the hobbyist, sometimes resulting in death or trauma. Note that in most cases, this does not necessarily mean they cannot be kept successfully in a home aquarium. We just want you to be careful!
Size: Grow too large for almost all home aquariums, requiring more than 1000 gallons, and in many cases, several thousand gallons.
Stress: Those species that are very sensitive and stress easily, do not transport well, and are susceptible to parasites and disease. This classification also includes species that only seem to survive in an aquarium when kept in large shoals (schools), and those that are collected from deep water, often improperly
Rare: Folks! If it is next to impossible to FIND a fish in the wild, collecting that species is a sure-fire way to drive it into extinction! To us, keeping these species is very irresponsible. We have two words for people that disagree with this . . . BITE ME!

Please note that some species may be on the list for more than one or more of these reasons, but not all reasons are shown due to space limitations. In our opinion, one or two reasons alone are enough to avoid that species, unless it falls into the category of being available as tank-raised, may be kept in an aggressive community tank, or is classified as poisonous, but easy-to-keep. Whenever we felt additional comments were necessary, we have added them in a row below the listed species.

Definition of Classes:
To clarify our position on listing certain species, while also conserving space in the following table, we have assigned a "Class" to each fish which correspond to the following comments. In some cases, this may seem redundant, but this is done to emphasize the importance of these reasons to avoid that species.

A - Fish that should never be kept in captivity, period.
B - Fish that may be kept successfully, but ONLY in public aquaria that can supply their specialized needs.
C - Fish that are often kept successfully in larger reef aquaria, but usually do not survive in fish-only aquariums. This is commonly due to specialized diet requirements that reef aquaria provide, in the way of naturally occurring micro-crustacean populations, but in some cases, may simply be due to the more complete natural ecosystem found in reef tanks.
D - Fish that are now bred and raised in captivity. Tank-raised specimens of these species will do well in aquariums, whereas wild-caught may not.
E - Fish that are almost always caught with Cyanide or drugs, and whose purchase supports this horrible practice.
F - While not impossible to keep in a home aquarium, requires either a specialized diet and/or habitat that make it impossible to keep with the majority of other species. Many should be kept in a dedicated tank. This classification is also used with very aggressive fish, or those that can eat larger fish, requiring special consideration when choosing tank mates.
G - Venomous. Exercise extreme caution when catching, or when cleaning the aquarium, and do not keep if you have small children.
H - Fish that should not be sold or purchased because they are rare. We felt the need to emphasize this one. Imagine public reaction to our hobby if it were discovered and published that the aquarium trade was responsible for the extinction of a species.

Note that we have also included certain invertebrate species, which we strongly feel are being exploited in the aquarium trade, or may inflict toxic bites or stings, capable of inflicting severe injury, or even death.

Butterfly Fish
Common Name	Scientific Name	Reason	Class
Copperband Butterfly	Chelmon rostratus	Diet	C
Marginalis Butterfly	Chelmon marginalis	Diet	A
Larvatus Butterfly	Chaetodon larvatus	Diet, Stress	A
Saddle Butterfly	Chaetodon ehippium	Diet	B
Myer’s Butterfly	Chaetodon myeri	Diet	A
Pearlscale Butterfly	Chaetodon xanthurus	Diet	B
Mertensii Butterfly	Chaetodon mertensii	Diet	A
Falcula Butterfly	Chaetodon falcula	Diet	A
Black Back Butterfly	Chaetodon melannotus	Diet	B
Blue Spot Butterfly	Chaetodon plebius	Diet	B
Blue Stripe Butterfly	Chaetodon fremblii	Diet, Stress	A
Burgessi Butterfly	Chaetodon burgessi	Diet	B
Dot-Dash Butterfly	Chaetodon punctatofasciatus	Diet	B
Double Saddle	Chaetodon ulietensis	Diet, Stress	A
Falcifer Butterfly	Chaetodon falcifer	Diet	B
Foureye Butterfly	Chaetodon capistratus	Diet	B
Fourspot Butterfly	Chaetodon quadrimaculatus	Diet	B
Coradion Butterfly	Coradion altivelis	Diet, Stress	A
Goldenstripe Butterfly	Chaetodon aureofasciatus	Diet	B
Gunther's Butterfly	Chaetodon guentheri	Diet	B
Latticed Butterfly	Chaetodon rafflesi	Diet, Stress	A
Lined Butterfly	Chaetodon lineolatus	Diet, Stress	A
Melon Butterfly	Chaetodon trifasciatus	Diet, Stress	A
Mitratus Butterfly	Chaetodon mitratus	Diet, Stress	A
Mulleri Butterfly	Chelmon mulleri	Diet, Stress	A
Ocellated Butterfly	Parachaetodon ocellatus	Diet, Stress	A
Ornate Butterfly	Chaetodon ornatissimus	Diet, Stress	A
Painted Reef Butterfly	Chaetodon sedentarius	Diet, Stress	A
Pakistan Butterfly	Chaetodon collare	Diet	B
Paucifasciatus	Chaetodon paucifasciatus	Diet, Stress	A
Raccoon Butterfly	Chaetodon lunula	Diet	B
Rainfordi Butterfly	Chaetodon rainfordi	Diet	B
Reticulated Butterfly	Chaetodon reticulatus	Diet, Stress	A
Semion Butterfly	Chaetodon semeion	Diet, Stress	A
Speculum Butterfly	Chaetodon speculum	Diet, Stress	A
Spot-Fin Butterfly	Chaetodon ocellatus	Diet, Stress	A
Spot-Tail Butterfly	Chaetodon ocellicaudus	Diet, Stress	A
Spotted Butterfly	Chaetodon guttatissimus	Diet, Stress	A
Teardrop Butterfly	Chaetodon unimaculatus	Diet	B
Triangle Butterfly	Chaetodon baronessa	Diet, Stress	A
Truncatus Butterfly	Chelmonops truncatus	Diet, Stress	A
Yellowhead Butterfly	Chaetodon xanthocephalus	Diet, Stress	A
Yellownose Butterfly	Chaetodon flavirostrus	Diet, Stress	A
Moorish Idol	Zanclus canescens	Diet	B
Obviously, many Butterflyfish do not live well in aquariums unless fed live corals and kept in large schools, feats best left to large public aquariums. There are however, many species that do not appear on our list. A very loose rule-of-thumb for selecting Butterflyfish is: Most Caribbean species are considerably easier to keep than most Pacific species. However, we must stress that this is not an absolute rule, as the Foureye Butterfly listed above, comes from the Caribbean, and the Longnose Butterfly, Forcipiger flavissimus, not on the list, is a relatively easier-to-keep species, usually collected in coastal Hawaii.
Angel Fish
Common Name	Scientific Name	Reason	Class
Heraldi Angel	Centropyge heraldi	Drugs	E
Heraldi Angelfish are almost always caught using drugs or Cyanide.
Flame Angel	Centropyge loriculus	Habitat	C
Lemonpeel Angel	Centropyge flavissimus	Habitat	C
Flame and Lemonpeel Angelfish will sometimes do very well in a fish-only aquarium, but that will depend on the individual specimen. They will always do much better in a reef aquarium. This is true of many Centropyge (Dwarf) Angelfish, most of which make great reef tank fish.
Bicolor Angel	Centropyge bicolor	Drugs, Habitat	C,E
Multi-Color Angelfish	Centropyge multicolor	Habitat, Rare	C,H
Golden Angelfish	Centropyge aurantia	Habitat, Rare	C,H
Shepardi Angel	Centropyge shepardi	Aggressive	F
The Shepardi Angelfish is only listed here because it is one of the most aggressive of the Centropyge (dwarf) angels. It should not be kept with other Centropyge species, or small, free-swimming, peaceful fish. The Eibli Angelfish, Centropyge eibli, can also be very aggressive towards other Centropyge angels.
Passer Angel	Holocanthus passer	Aggressive	F
The Passer Angel may be kept in an aggressive community tank.
Rock Beauty Angel	Holocanthus tricolor	Diet, Stress	B
Clarion Angel	Holocanthus clarionensis	Rare	H
Conspiculatus Angel	Chaetodontoplus conspiculatus	Rare	H
Goldflake Angelfish	Apolemichthys xanthopunctatus	Rare, Stress	C,H
Flagfin Angel	Apolemichthys trimaculatus	Diet, Stress	B
Regal Angelfish	Pygoplites diacanthus	Diet, Stress	B,C
Emperor Angelfish	Pomacanthus imperator	Diet, Stress	B,F
The Imperator angelfish is easily-stressed, very susceptible to lateral line erosion, and requires very clean water. Electrically grounding the aquarium, providing a diet with some sponge content, and using vitamin supplements will help prevent LLE problems with almost all fish.
Filefish and Triggers
Common Name	Scientific Name	Reason	Class
Orange-Spot Filefish	Oxynonacanthus longirostris	Diet, Habitat	A
Undulate Triggerfish	Balistapus undulatus	Aggressive	F
Queen Triggerfish	Balistes vetula	Aggressive	F
While the Undulate and Queen Triggerfish are extremely hardy, both grow quite large and will kill almost anything they can catch. These are not fish for any community aquarium.
Clownfish, Damsels, Chromis, Pseudochromis
Common Name	Scientific Name	Reason	Class
Red Saddle Clownfish	Amphiprion ephippium	Aggressive	F
Latezonatus Clownfish	Amphiprion latezonatus	Stress	C
White Cap Clownfish	Amphiprion leucokranos	Stress	C
Maroon Clownfish	Premnas biaculeatus	Aggressive*	F
The Maroon clownfish is only listed here because they will usually kill any other clownfish in an aquarium. This does not always occur, but the problem is common enough to provide a caution. Ephippium clownfish can be nasty!
Jewel Damsel	Microspathodon chrysurus	Aggressive	F
Neon Velvet Damsel	Paraglyphidodon oxyodon	Aggressive	F
Almost all Clownfish, Damsels and Pseudochromis are very hardy species that do well in almost any aquarium, but care should be taken with some species of Damsels and Pseudochromis, only because they can be extremely aggressive, even toward fish much larger than themselves. Most Chromis species are easily stressed, and are best kept in small schools only in reef aquaria.
Batfish
Common Name	Scientific Name	Reason	Class
Pinnatus Batfish	Platax Pinnatus	Diet, Stress	A
Tiera Batfish	Platax tiera	Stress	B
Eels
Common Name	Scientific Name	Reason	Class
Ribbon Eels	Rhinomuraena quaesita	Diet, Stress	B
Ghost Ribbon Eel	Uropterygius concolor	Diet	B
Banded Snake Eel	Myrichthys colubrinus	Diet, Habitat	A
Leopard Snake Eel	Myrichthys maculosus	Diet, Habitat	A
All Other So-called Snake Eels		Diet, Habitat	A
Snake Eels require a sand bottom, and feed only on crustaceans that submerge themselves in the substrate. Though we have kept one now for over a year by feeding it vitamin-loaded krill which we buried for it to find, this was an experiment, and of the four we purchased, only one was able to learn this trick.
Garden Eel	Taenioconger hassi	Diet, Habitat	A
Wrasses
Christmas Wrasses	Halochoeres species	Diet, Stress	A
Anampses Wrasses	Anampses species	Diet, Stress	A
Leopard Wrasse	Macropharyngodon meleagris	Diet, Stress	A
Most Other Macropharyngodon Wrasses		Diet, Stress	A
Orange-line Wrasse	Stethojulis balteata	Stress	B
Most Pencil Wrasses	Hologymnosus species	Stress	B
Laboute Fairy Wrasse	Cirrhilabrus labouti	Stress	A
All Cleaner (Labroides and other species) Wrasses		Diet, Stress	B
False Cleaner Wrasse	Aspidontus taeniatus	Diet	A
Lunare Wrasse	Thalassoma lunare	Aggressive	F
The Lunare Wrasse may be kept in an aggressive community tank.
Blennies, Dragonettes and Gobies
Mandarin Dragonette	Pterosynchiropus splendidus	Diet, Habitat	C
Target Dragonette	Synchiropus picturatus	Diet, Habitat	C
Scooter Dragonette	Synchiropus species	Diet, Habitat	C
Dragonette species graze constantly on small, live crustaceans, and seem to do well only in larger, very well-established reef aquaria. Dragonettes are often mistakenly called Blennies or Gobies in aquarium stores.
Parrot Fish
Common Name	Scientific Name	Reason	Class
Parrotfish	Scarus species	Diet	A
Parrotfish	Cetoscarus species	Diet	A
Parrotfish	Cirrhilabrus species	Diet	A
The Pygmy Parrot Fish, such as the Blue Pygmy and Bi-Color Pygmy Parrotfish (Cirrhilabrus species), may be kept successfully in peaceful communities, but are not as colorful as their coral-munching, larger relatives. Their diet in the wild includes some hard corals, but they also feed on a wide variety of reef organisms, making it easier to supply a good diet in captivity. As a rule, we do not condone the keeping of any Parrotfish species in home aquaria.
Anthias (Fairy Basslets)
Common Name	Scientific Name	Reason	Class
Creole Anthias	Paranthias species	Habitat	B
Blue Diamond Anthias		Habitat	B
Hawaiian Anthias	Miroabrichthys bicolor	Habitat	B
Purple Queen Anthias	Mirolabrichthys tuka	Habitat	B
Queen Tiger Anthias	Mirolabrichthys imeldae	Habitat	B
Female Squareback	Pseudanthias pleurotaenia	Habitat	B
		Habitat
Many Anthias species live in large communities, schools or harems, in and near crests, vertical walls, and tableaus of tropical coral reefs, feeding constantly on zooplankton. Some of these very colorful fish will only survive if kept in sufficient numbers to allow them to engage in their complex social relationships. Many that do well in reef aquaria, often require more feedings per day than most hobbyists can provide. Refugiums for cultivating plankton in the aquarium, will help to resolve this issue. Most Anthias species should not be kept in fish-only aquariums, and some should not be sold at all. Those Anthias that have a good record for surviving in aquaria, are almost always kept in reef aquariums.
Basslets, Groupers, Grunts (Sweetlips)
Common Name	Scientific Name	Reason	Class
Clown Sweetlips	Plectorhincus chaetonoides	Diet, Stress	A
Macolor niger Grunt	Macolor niger	Diet, Stress	A
Oriental Sweetlips	Plectorhinchus lineatus	Diet, Stress	A
Striped Sweetlips	Plectorhinchus diagrammus	Diet, Stress	B
Tangs
Common Name	Scientific Name	Reason	Class
Achilles Tang	Acanthurus achilles	Stress	B
Powder Blue Tang	Acanthurus leucosternon	Stress	B
Powder Brown Tang	Acanthurus japonicus	Stress	B
Clown Tang	Acanthurus lineatus	Stress	A
Chevron Tang	Ctenochaetus hawaiiensis	Diet, Habitat	C
Sohal Tang	Acanthurus sohal	Aggressive	F
The Sohal Tang may be kept in an aggressive community tank.
Lionfish, Anglers and Scorpionfish
Common Name	Scientific Name	Reason	Class
Fu Manchu Lionfish	Dendrochirus biocellatus	Diet, Habitat	B,F,G
Zebra Dwarf Lionfish	Dendrochirus zebra	Diet, Habitat	B,F,G
In our opinion, these are the only species of Lionfish that are difficult to keep, primarily because they bottom-feed, initially require live food, and cannot compete with aquarium fish that feed more aggressively. In the wild, they feed on small fish, cephalopods, and crustaceans. The rest of the Scorpaenidae species that are listed below are fairly easy to keep, but almost all are venomous, and some can prove deadly. We're not saying you can't or shouldn't keep these fish. We are saying: BE CAREFUL! Most Stonefish, Frogfish and Anglers cannot be kept with any fish up to their own size, as they have the ability to swallow fish that are almost as large as they are! Fish marked with an "F" classification will usually only eat live food.
Volitan (Peacock) Lion	Pterois volitans	Dangerous	G
Antennata Lionfish	Pterois antennata	Dangerous	G
Radiata Lionfish	Pterois radiata	Dangerous	G
Fuzzy Dwarf Lionfish	Dendrochirus brachypterus	Dangerous	G
Sphex Lionfish	Pterois sphex	Dangerous	G
Miles Lionfish	Pterois miles	Dangerous	G
Stonefish	Syanceia species	Dangerous	F,G
Sculpins	Scorpaenopsis species	Dangerous	F,G
Leaffish	Taenianotus tricanthus	Dangerous	F,G
Rhino Scorpionfish	Rhinopias frondosa	Dangerous	F,G
Angler Fish	Antennarius species	Dangerous	F,G
Threadfin Anglerfish	Nemanthias carberryi	Dangerous	F,G
Sea Goblins	Prionotus carolinus	Dangerous	F,G
Seahorses and Pipefish
Common Name	Scientific Name	Reason	Class
Most Seahorses	Hippocampus species	Diet, Habitat	F
Sea Dragon	Phycodurus eques	Rare	A
Sea Dragon	Phyllopteryx taeniolatus	Rare	A
Most Pipefish	Corythoichthys species	Diet, Habitat	F
Most Pipefish	Doryrhamphus species	Diet, Habitat	F
Most Pipefish	Syngnathoides species	Diet, Habitat	F
Trumpetfish species	Aulostomus species	Diet, Habitat	B
Many will disagree with placing Seahorses and Pipe Fish on this list, but the fact remains that many fail with these unusual fish. They are over-collected in the wild, both for the aquarium trade, and as dried ornaments. Some species are now successfully bred and raised in captivity. The main requirements for keeping these fish are a dedicated tank and providing a suitable diet. Other species, such as Seadragons (leafy seahorses) are now classified as endangered, yet still show up (illegally) in some fish stores. Trumpet fish, while much easier to keep, grow large, and almost always require live food.
Sharks, Skates and Rays
Common Name	Scientific Name	Reason	Class
Almost All Sharks, Skates and Rays		Size	A,B
Remora	Echeneis naucrates	Habitat	A,B
There are some sharks that should not even be kept by public aquariums. Remoras are hitch-hiker relatives of sharks, that attach to large whales and sharks, getting a free ride, and only detaching to feed on scraps when their "ride" grabs a meal. Without a huge whale or shark on which they can attach, they usually die a slow death. We've seen Remoras living and dying in public aquariums. We've actually seen them dying in aquarium stores! Why bother?
Boxfish and Cowfish (Trunk Fish)
Common Name	Scientific Name	Reason	Class
Blue Boxfish	Ostracion melegris (male)	Habitat, Stress	B
Black Boxfish	Ostracion melegris (female)	Habitat, Stress	B
Scribbled Boxfish	Ostracion solorensis (male)	Habitat, Stress	B
Scribbled Boxfish	Ostracion solorensis (female)	Habitat, Stress	B
Almost all Boxfish are very shy, slow-moving fish that usually cannot compete with aggressive feeding habits of other active community fish. They are easily stressed, susceptible to skin diseases and have few defenses against aggressive fish. Boxfish have the ability to release a toxin through their skin when threatened. In the ocean, this simply serves to discourage predators. However, if this happens in an aquarium, where the toxin cannot be diluted, all the fish in the tank will die. This has also been known to happen just before a Boxfish dies in a tank, even though they were under no threat from other fish.
Other Fish Species
Common Name	Scientific Name	Reason	Class
Shrimp (Razor) Fish	Aeoliscus strigatus	Diet, Stress	B
Pinecone Fish	Cleidopus gloriamaris	Habitat	B
Pinecone Fish	Cleidopus japonicus	Habitat	B
Flashlight Fish	Photoblepharon palpebratus	Habitat	B
INVERTEBRATES: Cephalopods
Common Name	Scientific Name	Reason	Class
All Octopus species	Octopus species	Diet, Habitat	B
Blue-Ring Octopus	Hapalochlaena lunulata	Dangerous	B,G
We listed the Blue-ring separately. A dwarf species, stores often sell them. Therefore, many hobbyists attempt to keep them. They are nocturnal and quite shy, so you'll hardly ever see them. They need a dedicated tank. Finally, if they bite you, injecting both of their highly-toxic neurotoxins into your bloodstream, you will go to the hospital, provided of course, you live to get there. Keeping any of the highly-intelligent Octopus species in a home aquarium is, in our opinion, cruel and unusual punishment, unless the hobbyist is willing to devote considerable resources, time, and study to their care. Only male specimens should be kept, if at all, as females of most species die soon after laying eggs. Selling an Octopus to an inexperienced hobbyist is an irresponsible and immoral act that should not be considered by any aquarium store.
All Squid species	Loligo and Sepioteuthis sp.	Diet, Habitat	A
All Cuttlefish species	Sepia and Sepioloidea sp.	Diet, Habitat	B
All Nautilus species	Nautilus and Argonauta sp.	Diet, Habitat	A
Squid require a lot of space for swimming. Cuttlefish require a wide, varied diet of live food and a dedicated aquarium. Nautilus are already over-fished for their colorful shells. Nautilus are nocturnal and undergo a daily, vertical migration. They require a cool-water, dark, and very deep, dedicated aquarium. Even in the proper environment, they experience buoyancy problems (they float), and are unable to properly grow new shell in captivity. In our opinion, only the Waikiki public aquarium is properly equipped for Chambered Nautilus, and even this facility has their share of problems with these ancient Cephalopods.
Other Invertebrates
Common Name	Scientific Name	Reason	Class
Flower Sea Urchins		Dangerous	G
Indian Cone Snails		Dangerous	G
Mantis Shrimp		Dangerous	F
Jellyfish		Dangerous	B
While some species of Jellyfish are not poisonous to humans, almost all live in open-water and require a dedicated, bare aquarium in order to survive. This is also true of the most commonly sold genus, Cassiopeia, also called the "Upside Down Jellyfish," a nocturnal filter-feeder which is sometimes sold to reef hobbyists, and rarely survive as they get trapped in rocks as they try to avoid the strong lighting used in these aquaria.

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If It Won't Live in Aquaria, Leave It in the Ocean!(The List)| Read Other Articles |

If It Won't Live in Aquaria, Leave It in the Ocean!
(The List)
| Read Other Articles |