Are fish tanks cruel?

Are fish tanks cruel? It depends. If the fish tank is too small for the fish or the equipment in it and water changes all in combination aren’t giving the right quality of water, heat and light then that’s cruel for at least those species of fish that aren’t being catered for. Fish also have the right to hidey holes where they can enjoy their privacy for the species that need it. Of course, some individuals within a species might need it more than others. Fish differ not only between species but within a species. They even differ in their behaviour within one spawning of fry. Such is life, for organisms that reproduce sexually. It is one of the so-called “joys of sex” that Alex Comfort neglected to mention as he was more concerned with the prurient. In fact, I hope my readers haven’t even heard of him.

BB Radio – einfach der beste Mix

The mix of fish is what people tend to get wrong the most though. Putting together fish of different sizes so that the smaller ones end up getting eaten is not fair on them. Also, you should not put fin-nippers or biters like barbs or puffer fish or overly playful fish like botias in with delicate fish which don’t like to be chased around, like discus or mormyrids. Everyone should know not to mix two male Bettas, but you could have a similar result over a longer period with a lot of kinds of cichlids. When you breed fish not taking care to have males and females from separate bloodstock, this also can lead to unintentional cruelty. That is because the number of young with genetic issues and deformities is likely to be higher.

Nuh’un gemisi sizin evdedir

If you avoid those problems, there is nothing intrinsically cruel about the aquarium hobby. Our well-maintained aquarium fishes have a much better quality of life much better than that in the wild. Whole species are now being maintained in hobbyist collections which are extinct in the wild. The German hobby and Hans-Georg Evers in particular brought the Noah’s Ark capability of our hobby to peoples attention already in the 1980s.

Many livebearers and even cherry barbs are maintained despite habitat destruction in captive collections.  Other hobbyists have gone so far as to describe species to science which they have found wither coming through trade channels or in their own explorations of the Amazon.

The image shows Brachyrhamdia marthae, named by my old friend and mentor Dr. David D. Sands in honour of his then wife. David Sands used to write many articles promoting non-cruel fishkeeping, avoiding for instance keeping very large fish like red-tailed catfishes in small fish tanks where they would not thrive.

I hope some aquarists reading this will aspire to be part of some cottage conservation project, and dedicate some nice tanks to this idea.

Aqua cuna vitae, ager nobis

So, you see why it depends. Depending on what you do with your tank it can be heaven or hell for your piscine companions. In itself it is not cruel, it is a set of panes of glass.

This is part of a new series where I bring over, updating and re-writing where needed, the best of my answers to questions on Quora. I made a few of these in earlier years in chronological order. For now, I am moving them in the order of the number of upvotes received. These being the ones I would most regret losing. That is what they threatened me with over there for not being a Neo-Marxist. Over the course of 2022, on even numbered dates in the months, I plan to bring home to as many of the best of these as I can manage. Where relevant, also to . I’ll be improving them, updating them, adding images. I warmly invite discussion below in each case. Enjoy!

Original Posting Date: 02/09/2017
Question as answered: Are fish tanks cruel?

Views at the time added to HTV: 13,600
Upvotes at the time added to HTV: 28
Comments at time added: 2
Shares 0

2 thoughts on “Are fish tanks cruel?

  1. When the topic of the cruelty of animal captivity is raised I always think we have to look at the alternatives left to the animals. Like many aspects of life, relativity comes into play. The major cruelty committed is that of the human animal depriving our fellow animals of their natural habitat. Of course, those responsible for the of taking the habitat are not in the least interested in the results of their actions. Those who do care about our fellow creatures (and I count myself among them) are left with only two options. Either captive breeding programmes with the provision of habitat as favourable as it is possible to give the captive species, or alternatively, allowing the species to become extinct.
    In the cases where the habitat provision is of the lowest standard (and I suspect these do exist) it might be argued that it is less cruel to let the species become extinct. A miserable, tortured life for any species has to be considered cruel and non-existence has to be better than that. Ideally though, we humans, who are the major cause of animal territory depravation and animal suffering, have an obligation to give animals an alternative that gives them a life worth living. We can do this and in many cases we do. Zoos (at least those in the West) have improved over the past decades and the level of psychological and veterinary care given is usually of a high standard. Monkey World in Dorset ( is a fine example of this where their “inmates” are rescued from a life of, at best deprivation (usually unintentional and caused by ignorance) and at worst a living hell (resulting from blatant sadism) to live a life as natural and as carefree as possible.
    So, yes, I think it is possible to enable fish to live in an environment that suits their needs and enables the species to survive, given sufficient knowledge, imagination equipment funding and conscientious attention to their welfare. The success of this depends on the keepers having sufficient empathy with the species to know when they are distressed or suffering and what the underlying cause of this is. Knowing the cause can then lead to changes to remove the problem. As with four-legged pets we learn to “listen” to their needs and by a careful monitoring of behaviour and body language learn to find solutions when things are not right. In an ideal world, treating others as you would wish to be treated yourself would apply to all living species. Alas and alack that isn’t often the case.

  2. That’s a very interesting set of considerations, Alan.

    Personally I do not think that any individual animal’s life is worth the same as a human life, however I have no doubt in my mind that a whole species is worth more than a single human life and therefore I would fight to keep the last breeding members of a species alive at least as much as I would fight to save someone’s life.

    But this idea leads in turn to a series of conundra, not to say dilemmata. Where is the cut-off for a species? Would you be ready to see a human die to save a subspecies? A rare breed? What about pest species that we all try to eliminate, should they be brought to the brink of elimination and then given a reprieve, as that old sentimentalist Imran Khan did for the polio virus as he presumably got it confused with the mint with the hole?

    Interesting considerations!

Your thoughts welcome, by all mean reply also to other community members!