Fish Pets Cat

“I don’t think the fish ‘understand’ that the cats are potentially dangerous”. This is a sentence written by a visitor on a forum about home aquariums.

If visitors to this page are looking for information about keeping a cat and aquarium fish in the same home, I hope it helps. It is quite an interesting topic and quite a complicated one; the main reason being that although we understand the domestic cat quite well because of the proliferation of millions of websites about the domestic cat over the preceding 5 years, scientists are still learning about fish.

cat fishing for goldfish

Until September 7th I will give 10 cents to an animal charity for every comment written by visitors. It is a way visitors can contribute to animal welfare without much effort and no financial cost. Please comment. It helps this website too which at heart is about cat welfare.

The aspect of fish which scientists are learning about is their level of intelligence and whether they have emotions and feel pain etc. which very much dictates how we relate to them. People tend to relate to animals in a hierarchical system meaning people tend to rank, for example, the domestic dog higher than a fish in an aquarium with respect to intelligence and rights. That may be misguided.

The question I have is whether it is sensible or reasonable to keep both cats and fish in the same home. It is certainly relatively easy to keep cats away from an aquarium. A lot of people use squirt bottles to scare the cat away from the fish which I’m afraid to say is unfair and wrong because it is a form of negative reinforcement which is what we call “punishment”.

However, despite that people use the squirt bottle against their cat to stop them going near the aquarium. Right away you can see a negative aspect in respect of keeping cats and fish in the same place.

The aquarium should be covered to protect the fish but I suppose some people don’t cover their aquarium. We know that sometimes cats, being fascinated by the fish inside an aquarium, try to hook them out with their claws (if they still have their claws because many in America are declawed). It may be the case in fact that some people who keep fish and cats declaw their cats in part because they wish to protect their fish. If that is the case then it is another negative impact in keeping cats and fish in the same place.

What about the fish? The question I have is this: even though a person can successfully protect the fish from the cat, fish are a prey item to the cat. Fish are not a primary prey item to the domestic cat, far from it, but given the opportunity fish could be a prey item. This probably comes from the wild cat ancestor which will feed on rodents primarily but living near watercourses might on occasions and where appropriate, prey on fish.

If fish are a prey item for the cat (or an interesting ‘object’ to catch) this begs the question whether fish recognise the domestic cat or any cat as a predator. Most fish have very well-developed sense organs. They have excellent eyesight. They also have good hearing. Hearing is an important sensory system for most species of fish.

Certain fish have a strong sense of smell. Experiments provide evidence that fish can feel pain and have fear responses – although, this is a developing area and more work is required. In aquatic environments, in this instance I am referring to the wild, fish are able to call upon information about the predation risk where they are from environmental cues gathered from visual, olfactory and mechanical senses.

A research paper says that “predator identity can be learned through socially transmitted information, direct encounters with predators or indirectly by associating a predator’s odour with an alarm cue”,  which is a chemical released by damage to the skin after having been attacked by a predator.

It would seem to me that if a cat had on one occasion grabbed fish out of an aquarium and the fish had survived then the fish would probably be fearful of the presence of the cat in the future. The big question is whether fish inherently have a hardwired fear of the domestic cat. If that is the case then the presence of a cat around the aquarium would stress the fish and be a disincentive to keep both cats and fish in the same home if one wants to be fair to the fish and if one is concerned about their welfare.

However, the fish aquarium websites indicate to me that fish are not bothered by the presence of a cat. A cat may have a habit of resting on top of an aquarium because it is warm. The reports I read on the aquarium websites indicate that this does not upset the fish but the information is anecdotal and there is no hard information about this.

I have to speculate in coming to a conclusion, which is this: there is a potential, at least, for fish in an aquarium, in a person’s home, to become stressed by the presence of a domestic cat in the vicinity of the aquarium but there is nothing to support that suggestion other than the fact that, as mentioned, fish have highly developed sensory systems and are predator-aware.


Part source: Plos One

8 thoughts on “Fish Pets Cat”

  1. I never understood fish.
    I may be wrong, but I think that they lack personality.
    I accept them as living beings, but I don’t know how to interact with them.

    • Dee, one day the world will realise that fish have tons of personality 😉 Seriously, as a species they are undervalued as sentient beings. They are treated as factory produced products. The factory is nature. They die by asphyxiation. A cruel death.

    • I think you have to get to know a fish to understand that they have personalities, ours would come to the side of the tank to us, or to the top when the lid was off for cleaning time.
      I used to talk to them, why not, I talk to all animals and birds and even insects, who knows what they can hear and understand.
      We humans think we are so clever but we are not anywhere near as clever as other species who don’t need words to communicate.

    • My mom had fish and definitely connected with them. She’d talk to them all the time and they’d swim to the side of the tank, seemingly responding. Maybe they just knew her as the one who gave them food, but sometimes I think that’s what Monty thinks of me (the food giver) so that’s not so different from how other companion animals relate (at least in part) to their humans.

      Mom’s fish Little Guy got just huge living in their fountain in the summer. He was probably too big for their indoor tank in the winter. He started out so small you could see through him. I think they won him at the Sauk County Fair. Fairs always have this game where you throw a ping ping ball at a table full of little gold fish bowls and whatever bowl your ball lands in you win that fish. They dump the contents of the bowl, water and fish, into a little plastic bag and you take that home. Barbaric really . This was several years ago. I hope that practice has been stopped.

      It’s sort of like how department stores used to give out free live baby chicks at Easter time. They even would dye them different colors. That’s how my mom and her sisters came to grow up with the legendary (in my family) rooster Peep– the rooster who thought he was a cat (he lived with all their cats) and liked to peck toes. Peep probably had a pretty good life for a department store chick until my grandma butchered him and cooked him for dinner because he was scaring away customers from their boat rental, and being frugal my grandparents were not going to waste what could be a meal. Except that, despite being pecked and terrorized by Peep for years, everyone was too sad to eat him.

      Little Guy had a very good life for a “fair fish”– I suppose most don’t survive very long. My parents’ outdoor fountain was not really deep enough for fish and a raccoon (or maybe a mink)scooped him out, took one bite and left him to die on the grass. My mom was heartbroken and vowed no more pets.

  2. Fish should be kept in as large a tank as it is possible to accommodate in the home and the tank should have a lid where the lighting and aerating equipment are housed, the lid should be adequate to protect the fish from cats but if the cat shows any inclination to sit on the tank lid it is vital to ensure that it is safe to do so from the point of view of the electric equipment as well as the physical safety and mental wellbeing of the fish.

  3. It should be perfectly OK to have both cats and fish in the home if a person is sensible about it. It’s cruel to use squirt bottles to chase the cats from the fish tank, it’s very easy just to put a lid on, the cats can watch the fish and the fish can feel safe.

    • I tend to agree that it almost certainly is okay to have cats and aquarium fish in the same home but as I mentioned in the article we don’t know enough about the mentality of fish. For example I remember a person criticising me for publishing a picture that I’d taken of a cat looking at 2 birds in a cage. It was a good photograph but he criticised me for taking it as I was being insensitive about the stress that the cat caused to the birds. I think he had a point to be honest. One day, I believe, that fishing will be banned because we will realise that fish are more intelligent than we had imagined.

      • I hope you are right about fishing being banned one day Michael! One of our brothers goes fishing and justifies it by saying he throws them back in the water, as do many who fish for fun. You can imagine how horrified Babz and I feel, being veggie we never eat fish, we never eat any creature who had a face in life.
        The whole concept of our power over animals and the way we make use of them is wrong, it’s not as if humans use them fairly like wild animals do in their food chain, we can take their lives any time we want too and far too easily.
        Fish are very intelligent and yes one day it will be realised, but that’s no help to the ones suffering now and it all makes me feel I don’t like this world the way it is but I’m trapped here.


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