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Caring for Fish

Fragile tropical fish, who were born to dwell in the majestic seas and forage among brilliantly colored coral reefs, suffer miserably when they are forced to spend their lives in glass tanks. The same is true of river fish. Robbed of their natural habitats and denied the ability to travel freely, they must swim around endlessly in the same few cubic inches of water.

Where Fish Really Come From
The popularity of keeping tropical fish has created a virtually unregulated industry that catches and breeds as many fish as possible with little regard for the animals themselves. While many species of coral are protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora, most of the fish who end up in aquariums are not.

An estimated 95 percent of saltwater fish sold in pet shops come from the wild, mostly from the waters around Indonesia, the Philippines, Fiji, and other Pacific islands. More than 20 million fish, 12 million corals, and 10 million other types of marine life—such as anemones, shrimp, and mollusks—are captured every year to support a $300 million worldwide “hobby.” Some species, such as the Banggai cardinalfish, have become endangered because of overfishing, a practice commonly employed to satisfy the aquarium industry.

Collectors douse the coral reefs with cyanide, which is ingested by the fish who live there, and as reported in Scientific American, “[t]he resulting asphyxiation stuns some fish and sends others into spasms, making them easy to grab by hand or net.” Half the affected fish die on the reef, and 40 percent of those who survive the initial poisoning die before they reach an aquarium. Cyanide also kills the coral reefs themselves, and marine biologists rank it as one of the biggest dangers in Southeast Asian waters.

Approximately 90 percent of freshwater fish are raised on farms. Goldfish, for instance, are usually bred in giant tubs in facilities that produce as many as 250 million fish per year. These animals are sold to zoos, pet stores, and bait shops, and many are doomed to live in plastic bags or bowls, neither of which provides the space or oxygen that goldfish need. The city of Monza, Italy, banned keeping goldfish in bowls because the containers do not meet the needs of the animals and because, as one sponsor of the law pointed out, bowls give fish “a distorted view of reality.”

Some fish farms are seeking new market niches by creating fish breeds that would never occur in nature, treating fish as ornaments instead of living animals. Some breeders even “paint” fish by injecting fluorescent dyes into the animals’ bodies or altering their genetic makeup to make them more attractive to buyers.

Fish Can Speak, Make Tools, and Think 
Fish have cognitive abilities that equal and sometimes surpass those of nonhuman primates. They can recognize individuals, use tools, and maintain complex social relationships. Biologists wrote in Fish and Fisheries that fish are “steeped in social intelligence, pursuing Machiavellian strategies of manipulation, punishment and reconciliation, exhibiting stable cultural traditions, and co-operating to inspect predators and catch food.”

Fish communicate with one another through a range of low-frequency sounds—from buzzes and clicks to yelps and sobs. These sounds, which are audible to humans only with the use of special instruments, communicate emotional states such as alarm or delight and help with courtship. The pumps and filters necessary in many home aquariums can interfere with this communication. “[A]t the least, we’re disrupting their communication; at worst, we’re driving them bonkers,” says ichthyologist Phillip Lobel.

What You Can Do
Please don’t support the tropical fish trade by purchasing fish. If you enjoy watching fish, consider downloading one of the many colorful and realistic fish-themed computer screensavers available on the Web. Don’t support businesses or fairs that give fish away in contests or promotions. In the United Kingdom, it is illegal to give fish as prizes or sell animals to children under the age of 16, and guardians must provide a “suitable environment” for all animals. A similar law is in effect in Reggio Emilia, Italy.

Siamese fighting fish, who are often sold as “decorations” or party favors, are fighting for their lives as their popularity grows. Pet shops, discount superstores, florists, and even online catalogs sell Siamese fighting fish (Betta splendens) in tiny cups or flower vases to consumers who are often uneducated about proper betta care. These tiny containers are not suitable for any fish.

Biologists say that there is no safe way to return captive fish to their natural environments—which are often located in a completely different region of the world—because of the difficulty in locating such a habitat and the possibility of introducing disease to the other fish there. Researchers have found many species of non-native fish, including predatory species, living off the coast of Florida, and they attribute these populations to careless aquarium owners. These fish pose a real threat to native species. Never flush fish down the toilet in the hope of “freeing” them, as seen in the popular movieFinding Nemo. Even if a fish survived the shock of being put into the swirling fresh water, he or she would die a painful death in the plumbing system or at the water treatment plant.

If you already have fish, you can make their lives easier by providing them with an environment that is as much like their natural habitat as possible. While captive fish can never live natural lives, the following tips will help ensure that they are as happy as possible:

  • The more space that fish have, the happier and healthier they will be. Their needs vary, so check with an expert or consult a good fish book to determine their requirements. One general guideline is that you should provide 3 gallons of water for every 1 inch of fish.
  • Treat tap water properly before putting it into the aquarium, as most municipal water contains chlorine, which can kill fish. The type of chemicals that you should use depends on your area’s water. Consult with a local tropical fish supply store to determine the proper treatment.
  • Different types of fish require different pH levels. Check the pH level daily for the first month and weekly thereafter.
  • A filter to remove waste particles and noxious chemicals from the water is essential. Live plants help with this task and provide oxygen, shelter, hiding places, and the occasional snack.
  • A properly working air pump is necessary to provide oxygen.
  • Fish need a constant temperature, generally between 68°F and 76°F, but you should check with a fish supply store for information that is specific to the type of fish that you are keeping. Automatic aquarium heaters monitor the water temperature and turn the heater on and off as needed. Attaching a small thermometer to the tank will help you ensure that the heater is functioning properly.
  • The natural waste of fish emits ammonia, which can accumulate to toxic levels, so clean the tank regularly, but never empty the tank completely. Be sure to clean the glass well with a pad or a brush to prevent algae growth.
  • Create places for the fish to hide and explore. Ceramic objects, natural rocks, and plants work well. Make sure that all objects are thoroughly cleaned and disinfected before they are put into the tank. Do not use metal objects, as they will rust.
  • Be aware of the environment outside the aquarium. Suddenly switching on a bright light in a dark room can startle fish, and vibrations from a television or a stereo can alarm and stress them.
  • Keep all harmful chemicals away from the aquarium. Cigarette smoke, paint fumes, and aerosol sprays can be toxic if they are absorbed into the water.
  • The aquarium should be in a spot where temperature and light are constant and controllable. Tropical fish supply stores may be able to advise you on the best amount of light for the fish you are keeping. Remember that direct sunlight and drafts from nearby doors or windows can change the water temperature, and fumes from a nearby kitchen or workshop can injure the fish.
  • Don’t overfeed! Uneaten food and waste material are broken down into ammonia and nitrites, which are toxic. One expert recommends providing only as much food as your fish can eat in 30 seconds.
  • If a fish seems sick or lethargic, take him or her to a vet. Fish can be medicated, anesthetized, given shots, and operated on, just like other animals. Take along a separate sample of the tank water.
  • Most fish enjoy companionship. If you have a single fish, check with friends and neighbors to find another loner to adopt—but don’t support the fish trade by going to a dealer.
  • Supply stores and catalogs have clear plastic dividers available that can be used to create a safe section in a large tank for a betta fish who is living in a “community” aquarium. Make sure that the divider fits securely in the tank and provides necessary access to the surface.
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  • MJR says:

    I keep a lot of fish, including 3 Bettas. I do nothing but love my fish and have invested a lot of money in making sure they are healthy and happy. I only feed a variety of food that they would normally eat in the wild. I keep a variety of live and fake plants and a bunch of hide-aways for them to pick and choose. I spend time with my fish everyday and spare no expense when it comes to food, filters, heaters, ect. I have no reason to be sorry about keeping fish, I am also currently working on setting up a 50 gallon tank to get even more fish, which I buy from a variety of pet stores near my home.

  • Malinda says:

    That’s the best aswenr of all time! JMHO

  • Elissa says:

    The people commenting that it’s okay to keep fish that have been bred but not okay to catch them in the wild are so backwards. The lesser of the two evils would be the wild caught because they were allowed some life before their confinement. Fish hatcheries are no different than any other kind of factory farm and a huge percentage never make it to the pet store. I worked undercover at a pet shop (now shut down) and we were required to collect the “floaters” every morning and if more than a third of the fish delivered were dead we were given another garbage can full. I understand this is your hobby but give it up! I currently care for 2 rescue fish, check petfinder if you must own fish. But ask yourself, “why do I feel the need to own someone?”

  • Kate says:

    Zepheroh31 , many fish ARE bred in captivity. In fact, hardly any aquarium fish today are caught in the wild. The only ones I can think of off the top of my head are plecos, some reef fish, and obviously fish that are sold as wild fish. I personnaly love breeding fish, bettas (Betta Splendens) in particular. i am on my third spawn at the moment, and in a few weeks the fry will be ready to go to their new homes. Also, I’m just curious – what type of fish is Gill? And how many years have you had him?

    But in response to this article, I think it’s a bit of an overcorrection to simply stop buying fish, period. Even if 500 people stop buying fish, there are still millions of people buying and selling fish out there, and millions of fish still being tortured. In my opinion, it would be better to speak with the managers/owners of fish-selling companies about their methods of acquiring fish, selling them, tank sizes they sell, etc. If we ignore the problem completely, nothing will be done for these innocent fish. Instead of refraining from buying the fish and thinking, “oh, well by not buying this fish, I saved its life AND discouraged pet stores from selling fish!” NO! That’s not what you did! You simply neglected to help possibly hundreds, even thousands, of fish by encouraging the proper store care of fish. Please don’t turn a blind eye to this problem, like this article suggests. Help the fish. Save lives.
    (Wow, this is sounding a lot like one of those ads to help starving kids in Africa or something!)
    Also, if you are interested in buying a betta, please contact Faith from She breeds her own bettas in small spawns. The bettas are a bit more expensive (ok, a LOT more expensive) but it is absolutely worth it if you are a truly responsible fish-keeper. These are beautiful fish, too!

  • Zepheroh31 says:

    Wow, I had no idea how the fish we own in our homes were captured. Thats REALLY sad. why cant they just breed the fish they have?! (no over breading) I don’t really want to give up owning fish, but now i kind of feel sorry that i do. I got this one fish when I was 8 and its still alive today. I named him “Gill” after the finding nemo charater. Kinda surprised hes still alive you know? Its a bit of a long life for a fish.

  • Jeremy S. says:

    Good advice for the most part, but I might add:

    1. Never place a fish into a tank that has not been fully cycled. This is the #1 cause of death and disease in domestic fish. If you don’t know what “cycled” means, Google “aquarium cycle”.

    2. Always research your fish. Not all fish can live together. Also, some species, like all tetras and corys, need a minimum of five of their kind. Others, like cichlids, need their own territory.

    Also, I question the wisdom of keeping a betta in a community tank, even with a divider. The poor guy would be flashing his gills all day and going crazy. I think eventually the stress would kill him. Bettas also require low-flow filters and acidic water with a lot of live plants (plastic can hurt their sensitive fins).

  • Abhijit says:

    I dont know what to say…. about it…. coz its all about responsibility…. nothing else…. For me its a form of art…. communing with nature…. but I don’t know PETA says not to watch them…. I am fine but then downloading a software wont be communing with nature…. just like downloading a nude pic doesn’t make me love a person…. I dont know…. coz its all complicated…. IN the way of saving animals…. PETA may create hell for them…. coz we delete what we dont communicate with….

  • Marike Postma says:

    After reading this i feel quilty about having an aquarium. Althoug my aquarium is big, i promise now that from this moment on i will not buy any more fish and i will spread te word!!!

  • Rainy says:

    When I was 6, my parents got me a Betta fish. I called him Bluespikey(I was 6!!!!). We kept poor Bluespikey in a tiny fish bowl on the dining room table. Since I was 6 and knew nothing about proper animal care, I fed Bluespikey these “mealworm fish food” stuff. Bluespikey lived for about a year before dying. Now, I feel horrible about what I did. R.I.P Bluespikey. Now I realize how cruel I was, and how Bluespikey must have suffered. 🙁

  • Annaliesa says:

    I keep fish – my father bred prize-winning pastel guppies when I was a child. He went to great lengths to not allow the fish to be inbred (We had three 20 gallon tanks and one 29 gallon tank), and we kept live plants, snails (Which we did not kill) for algae control. The tanks had proper equipment. Death was extremely rare.

    I have a few more tips to add:

    1. While buying many animals from breeders is unethical, try to buy fish from a reputable breeder. Many fish breeders have a passion for fish, and do their utmost best to raise healthy fish. Ask to see their tank setups, if possible. Local fish shows can be a source of referrals.

    2. Pick fish that will thrive in your tap water conditions to an extent. For example, if you have hard water in your area, it is best to purchase fish that thrive in hard water. If there is soft water, buy fish that do well in soft water. You can treat water with chemicals and aquarium salt if necessary, but it is best to select fish that do well with your local tap water. This will save you a lot of work! If you are an advanced fish keeper, you can purchase reverse osmosis water from a pet store or buy a unit yourself. Note that you will need to add some amount of minerals to the water – no fish lives in mineral-free water.

    2. Do not use fish to cycle (providing needed bacteria to keep fish and plants healthy) your tank. Some owners will place a “throw-away” fish in their tanks. This is cruel and unnecessary. Look up “fish-less cycle” on the Internet for instructions.

    3. Avoid using medicines, algae killer, or snail killer to your tanks at all costs. This will make your fish sick, and upset the natural balance of your aquarium. Almost always fish get sick from environmental factors. Have a separate cycled “hospital tank” when your fish get sick. Check your water parameters and change water (guidelines will vary – research). When the water becomes healthy again, add the fish back to the main tank once it has healed.

    4. Avoid netting live fish. This is especially true for Angel fish. Using a net can be very traumatizing.

    5. Make sure your fish play well with others. Some fish need to only be kept with the same species. Some fish are aggressive (African and New World cichlids are fish I frequently see in stores and cringe at the thought of a naive fish parent purchasing). Some fish school, so make sure to buy enough fish to keep them feeling secure. Some fish can be passive, so keep them with other passive fish. Etc. And of course, only select fish with the most similar water parameters as possible!

    On a related note, there are aquarium mates you absolutely should not buy. The most notable is the Chinese Algae Eater. They are sold in pet stores as cute little fish. They start off as mostly algae eaters, but as they grow (To atleast a foot long), they become hostile to other fish – they will feed off of the slime coat of fish, and will eventually be able to eat other fish whole. Shady pet stores will frequently sell these as “gold algae eaters” or simply “algae eater.” Absolutely do not support the purchase of these fish. If you happened to buy one of these on accident, remove the fish immediately from the main tank and place it in it’s own tank. These are of the few fish that do well alone. If you cannot keep this fish, contact a vet or breeder to humanely euthanize the fish.

    Also, you may see aquarium frogs at the store. Be warned: there are two types of frogs often sold at pet stores. One is the African Dwarf Frog, and one is the African Clawed Frog. The Clawed Frog becomes very, very large and predatory. Both look extremely similar when young. Find photos and talk to other fish keepers about how to identify these frogs. Should you have purchased a Clawed Frog, give it it’s own tank or find someone to adopt it. There are people who find the Clawed Frogs engaging.

    6. Speaking of algae eaters, no fish will be able to survive on algae alone. They will need supplemental feedings. Also, they often do not eat all types of algae. Do not purchase algae eaters for the purpose of “cleaning” your tank. Pick ones you like – they can be entertaining to watch! There are non-chemical methods of removing algae – use one of those.

    7. As for food, different fish have different dietary needs. Some fish are obligate carnivores. They do not have the digestive tract to eat plant matter. Do not give them feeder fish! They are usually sickly and kept under cruel conditions. You can raise your own daphnia, worms, brine shrimp, etc. in a suitable manner.

    Omnivores vary in their need for vegetables or meats. Some omnivores need more meat and some need more vegetables. Feed appropriately.

    If you are opposed to feeding your fish meat, there are fish that are pretty much vegans. Research, research, research!

    Generic, “all types of fish/fresh water species/marine species” foods are not appropriate for your fish. Each breed has individual dietary needs, and generic flake food cannot meet those.

    8. Bigger fish tanks are easier to care for. The absolute minimum size tank you should purchase is a ten gallon tank, with the exception of hospital tanks or fry (baby fish) tanks. Those can be five gallons depending on the fish breed. Absolutely do not buy fish bowls or anything under five gallons – those things are useless for everything except for art projects.

    That is all I can think of. Great article!

  • SJ says:

    hi i have a fish and i should have read this article before i bought him! Although he is really happy, i agree! If people buy a fish they should really take care of them.I felt REALLY bad.:( i didn’t know i was being cruel!But fish need nurture and care just like dogs and cats!!!

  • Karen says:

    I am a PETA supporter and love animals and still was stupid enough to buy fish without sufficient knowledge. I saw them swimming around in crowded tanks in the pet store and felt I had to save at least some of them. I bought the best products and read a lot on proper care on the internet and committed myself to being the best fish owner out there. I trusted the people at the pet store to educate me fish pairing. I didn’t think the pairing could be as complicated as it actually is. The fish species I was sold did not get along and two of my poor fish died which I believe was due to stress. I have never been so heartbroken and disappointed knowing that as an animal lover I have failed and I imagine there are people worse than myself out there giving even worse care to these poor beings. I hope that there can be more awareness around this subject so that no one can make the same mistakes I did. Pet stores should not be able to sell you incorrect fish pairings. I know it’s my fault too and wish I had read this before 🙁

  • Joseph says:

    I have fish in 20G, I was devastated when I realised that I could be an animal crueltist. Though I read the required fields and I did everything. The only problem is that I still live with my parents, and so does my brother, just to tick me off he jumps around near my fish tank and you can see them freak out (I hate him.)Anyways how about fish that aren’t caught in the wild and are kept in the said conditions. As well is their anything that can be done about the filter? (P.S I want a bigger tank so even better.)

  • Sergey says:

    catty fox (and anyone else) before buying my first fishes(when I was 16) I spent 2 month reading about the fishes I was going to buy and during many years none of my fishes died. Please people before buying a pet please LEARN about them. It’s your fault if your pet dies, not the guy’s who sold the fish.

    P.S. Sorry for my bad English.

  • catty fox says:

    I got two goldfish for my 18th birthday and being a lover of all animals i was so happy! I wish i’d read this article back then, they might have had a better chance at survival. I cried hours when they died. I really did try my best but i didn’t know how messy goldfish are and how ill equipped they are to deal with leaving in a small tank. I’m glad i know a lot more now – i’ll never buy a fish.

  • Madeline says:

    This article made me so happy I cried. I have been searching everywhere for some kind of opposition to the stealing of fish from the wild as pets, and .this is the only one I have found. I have had a goldfish for a while, and he has a lot of space and is happy; I would never have bought him if I’d read this article first. Well, there was algae on the tank so I decided to get an apple snail from the pet store. When I got to the pet store, they told me not to buy a snail, but to instead buy an otocinculous catfish. They said the goldfish would leave the fish alone, but would try to eat a snail. I took their advice and bought the otocinculous, even though I didn’t know anything about it. It was so stupid and I’ll regret it forever. I did some research and discovered that Otto Catfish are caught wild in South America, and most of them die before they even get to the pet store. If not, they usually die within a week of being introduced to the aquarium. That’s what happened to my fish. Every person I’ve heard of that owned one said, “They’re great, but they all died within 10 days, so I bought some more.” If people realize that these fish can’t be kept, and they know why, why is it that they continue to buy these fish and endorse the capture of these wild animals? There is so much opposition to keeping monkeys and chinchillas and wolves as pets, but everybody loves exotic fish. I just don’t understand.

  • Philippa says:

    Hi Peta,
    I’m a marine biologist in South Australia and I’m very pleased to see an article on fish. I agree with almost all of the comments with exception on one – noise. Yes pumps, filters and aerators make lots of noise but if you put your head in the ocean… well it’s pretty noisy down there too. Where I live there are millions of tiny shrimp under the sand and the noise they make sounds like cicadas on a warm summers night (wonderful to hear really). In my opinion, the noise pollution from boats, submarines (and their sonar), surveying etc is much more detrimental to ocean animal’s communication and food finding abilities. I have seen fish ‘look’ terrified when their owners play loud music (or music with the bass on high) – the excessive vibrations in the water send the fish cowering to a corner or behind the nearest shelter. I feel that if you are going to keep fish it is essential to have adequate filtration and air, which means, some noise. The benefits of having these mechanical devices running far outweighs the noise factor. Fish are very sensitive creature and we should take care of them.