Throwing a wrench into the mechanics of minimum fish numbers… well, sort of…

[Magnum Man]

So as got mentioned in a different thread the other day, I often bump heads with people, and posted “facts” on minimum fish numbers… often these are put out there without any thought to the development of the fish…
I’ll admit, there are a lot of fish, for example, in the tetra family, that stay small, and are social throughout their development, but numbers are assigned to too many fish out there, that may look to feel more “comfortable” in larger groups, when they are fry, but by the time they are mature, command more turf, individually than is allowed in most aquariums, many catfish, and cichlids fall into this category… then there are fish like Tin Foil barbs… a large fish, that is extremely neurotic, as babies, still small enough to need companionship but big enough, it can be challenging, as they grow bigger, and as they get quite large, are often seen as singles, in tanks when they mature, but this is one fish, that is larger but actually social, even as they mature… I have 5 adults right now, and I’m rewarded with witnessing their adult social interactions… however, they do seem fine as singles, in tanks, when mature, but totally freak out, when smaller when not in a minimum group… I think there is a lot of information yet to add, to minimum numbers, on a lot of fish….

One of my pet peeves, is when we use words that imply we know how fish feel ( above I used the word “comfortable” in quotations ), because that is a “feel” word, that was easy to use in the sentence… but if we were really concerned with how fish feel, most fish if questioned, would probably rather not be in an aquarium at all… the real question, we should be asking ourselves, is do I get enough enjoyment from these particular fish, to encase them in a glass cage for their whole lives, and what can I do to make them as “comfortable” as possible while they are in my care, and as they mature from often sold fry, into adulthood…

 

[GaryE]

Personally, and only for myself, I avoid large fish now. I can't justify putting them in tanks - I'm not of the monster fishkeeper persuasion though I know people who do a great job of it.

If I had space and budget for 16 foot long huge tanks, I'd have Satanoperca daemon in one. But I don't, and every time I see juveniles if that species, I pass.

There are fish like bala sharks, goldfish, giant gouramis, common plecos and such I think shouldn't be in the general trade. If people want to special order them, okay. But if I had the pet shop of my dreams, they would never be sold. There would be no tankbusters. And, I'd probably go bankrupt for that.

My solution to the idea of how to do it right? If you want more fish, you must have more tanks. It's easy to avoid crowding if you have space and money. Both are luxuries for most of us. when we're new at it, we calculate how to add just one more fish. We're driven by curiosity and challenges, like garden people are. We tell ourselves that when the tiny fish we know will grow gets too big, we'll buy a bigger tank. We rarely ever do - those are famous last words in this hobby.

I don't want to sidestep one of your questions - do I think the entire hobby is ethical? As it's organized now, it may not be. I'm an ape playing with its food. We do tend to use other animals, and this is part of that. I know I won't get enjoyment form mistreating a fish, and how I define mistreatment may be different from how you define it. To me, a large fish deserves an immense tank. I can't provide that, so I don't encourage the trade in them.

 

[Magnum Man]

@GaryE … side tracking my own thread, but looked up the fish you mentioned, and according to Seriously Fish, a ph starting at 3.5 to 6… I honestly don’t know how anyone could maintain a ph that low in a tank, with proper water changes ( coming from a guy in a hard water area )… my best is running straight RO, and a few natural softening agents like drift wood, and almond leaves, gets me in the middle to low 6’s … I just can’t imagine getting the ph that low, or even getting mine lower than 6…

 

[GaryE]

That's where one size fits all fish theorists fall on their faces. My tapwater comes from tannin stained lakes with a low pH and very low mineral hardness. The city adds agents to protect the pipes, and to harden the water and make it temporarily less acid. So what I would deal with choosing the perfect fish may not be what you'd have.
I deal with different water all across the board - ammonium vs ammonia, etc. I'd have different fish choices than someone who lives up the hill in my own city, an area where the water is drawn from deep hardwater alkaline wells. Even in one small city, things can be radically different.

 

[WhistlingBadger]

Interesting. Is it better to keep a large fish by itself so it has adequate space, or to overcrowd but provide adequate social interaction? The answer, of course, is neither. Plan for adult size and numbers when stocking a tank. I know both Gary and Magnum basically already said this, but I thought I'd just repeat it for any beginners (and a few of us experienced but hard-headed keepers).

As for the ethics of the hobby, and fish preferring not to be in a glass box...I don't know if it's that simple. It seems to me that, if you set up your tank right, your fish won't be aware that they're in a glass box...they've simply found themselves in a smallish pond or river, with one bank inexplicably transparent and populated by these large moving things that seem to appear just before food arrives. Fish, as a whole, don't seem to be deep thinkers. A well-kept fish in captivity is generally going to live longer than a wild fish due to lack of predators. So maybe what we're doing isn't so bad after all.

Of course, the qualifier is "well-kept." Many, perhaps most fish aren't. But as for me, I really don't think my wild-caught fish realize they're in a glass box. As far as I can tell (and admittedly I'm assuming here, as they don't say much), they really don't seem to think about it. They're too busy living their lives, interacting with each other, frolicking in the current, and mugging for food from that big blob that occasionally appears in the transparent river bank.

 

[CassCats]

Re: the grouping thing

Generally we should provide fish with what they'd expect naturally in the wild to the best of our abilities. This includes socially. So seeing how they behave in the wild is helpful, because if in the wild they tend to be among groups, then that is what we should provide to them in captivity. A minimum is just that, a starting point where folks notice that skittish behaviors or aggressive behaviors lessen at, so that's typically why it's recommended to start a group at "6" for example. Naturally, yeah bigger groups are better, but a baseline was figured out based on fish behavior to determine which is better to start with.

And "give fish what they expect in wild" doesn't mean setting up a perfect replica of nature though either. Fish expect: social needs met, shelter, correct substrate or materials to perform particular behaviors they evolved to do, and water parameters they evolved with. You can replicate the shelter aspect with fake plants or live plants, fake caves, etc.


It is definitely a complex topic, one that there isn't a one size fits all thing.

My opinion, we should provide a group as large as we can while also providing the space to do so.


I'm a goldfish keeper, initially by an oops, but I'm probably the exception where when I planned to upgrade, I meant it. I caught my common guy as a tiny baby when netting tadpoles with my kid out of the river here. Would have been irresponsible to release it back, and I know most in the hobby would have just kept the common goldfish in a tiny tank his whole life.

And this ties back into the numbers thing, but got him 2 fancy companions so he's got goldfish friends because goldfish are very social. But, space is limited with adult size, so where do you start and where is your limit, you know? Hes in a 6 foot tank, but even that can't fit a whole huge group lol

 

[Colin_T]

Generally we should provide fish with what they'd expect naturally in the wild to the best of our abilities. This includes socially. So seeing how they behave in the wild is helpful, because if in the wild they tend to be among groups, then that is what we should provide to them in captivity. A minimum is just that, a starting point where folks notice that skittish behaviors or aggressive behaviors lessen at, so that's typically why it's recommended to start a group at "6" for example. Naturally, yeah bigger groups are better, but a baseline was figured out based on fish behavior to determine which is better to start with.

Well said

 

[Naughts]

We need to simplify things to get a succinct starting point of basic understanding. That is where minimum numbers come from.

After that, we can become more specific, detailed and verbose in our considerations, such as the life stage of a individual fish.

This can become quite sophisticated but unfortunately most fish keepers will not put the fish first. Most minimum numbers will be insufficient (6 is not enough for small fish, timid fish, nippy fish and so on) yet the average inexperienced fish keeper will want smaller, not larger group sizes. Maybe this is akin to the ‘Noah’s Ark’ community fish tank where the keeper wants to try 2 of every species and thinks they are then experienced in keeping all of them, when actually they are getting a very poor experience. Not only are they not seeing the true expanse of behaviours and interactions; but also the visual impact of shoaling fish in sufficient numbers is such a wonderful sight to watch.

Byron had linked a scientific study but unfortunately I cannot source it or remember who wrote it. @Essjay, please can you help? It was a good example, and the issue of group numbers comes up in nearly every ‘stocking a new tank’ post.

From Byron’s posts:
the study found that shoaling fish are programmed to live in large groups and needed a shoal for safety and security and to establish hierarchy. It showed that fish that were kept in numbers less than ten, had high stress levels, shorter lifespan and latency to feed.
We might say our shoaling fish kept in small numbers are not stressed because they ‘don’t look it’. But the stress is guaranteed. Stress may or may not be visible but it will be causing internal issues we can't see. And the fish live a shorter than normal lifespan as a result. They frequently die from some other issue brought on by the stress, but even if they somehow manage to get past that, their lifespan is always less than what it should be in better conditions.

 

[Essjay]

I've found this -

You can do a search on Google Scholar, under "shoaling fish" and similar. One good study is this one.

https://d1wqtxts1xzle7.cloudfront.net/50054534/The_effect_of_group_size_on_the_behaviou20161102-6716-1m0ezpq-libre.pdf?1478088417=&response-content-disposition=inline%3B+filename%3DThe_effect_of_group_size_on_the_behaviou.pdf&Expires=1688573649&Signature=ceO6DPGB1gHwJadgET3gpG3R73uuuZOEtZjxukOc3I-XsbUcLEi1VtFgdKZ-9CsO4u5C5A0LiPdlS5t1TUw3GIS57dAB3dm7VDAb5Y1EeXAWHtPuH3MyYTyhVGUIy8CdwWJ0J5E4mGtjfC-jneN-YJZBL4RE6TH78BsUCmCzhBz0lJ0GvbLyvfI5takEDVHKEOS5cUUXoInaMKP-gx~yo6FB2~g~gs37oQJby~PtjmFa39vJbPb6UXhql05mUL4BV0MW32tfZn9rWBkCRySWm9DXUHwDn6uQNAqxTOEuCfPERrRDgqOCjH5twFr67Aw9d3d0IxPRYeud0xZcCWt2tA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA

 

[Magnum Man]

@Naughts … I like your”Noah’s arc” analogy… and I do have 2 tanks that fit that description… my African Tetra tank, and my Hillstream loach tank…both of these I think I’m getting away with it… because I think a lot of Tetras while being a shoaling fish, will shoal with other tetras, if numbers are lower than they may like of their own species I witness this is my South American tetra tank, that has a minimum of 6 of each species, several species spend the bulk of the day, swimming with another species… in my “Noah’arc” tanks I typically buy 3 of each… Hillstreams are listed as social, and they completely interact with each other ( dare I say… play, with each other ) I don’t think I’d see a significant difference, if they were all one species…

This is a departure from aquarium fish, but, we call them bullheads around here ( a relative of the catfish ) these can be seen in clouds of 100’s in the local lakes, when they are fingering size… strength in numbers… but by the time they are half grown, they have become solitary critters, probably because food sources couldn’t support 100’s of them together as anything bigger than fry… I personally think a lot of the same happens with aquarium fish, often captured or sold at fry size, they may want to hang together for the same reasons, but by the time they reach sexual maturity, they want nothing to do with each other…

 

[GaryE]

I like to watch a lone bee at work, but the hive is where the honey is.

The thread is at cross purposes. One one side, there's the importance and value to the aquarist of larger groups. On the other, there's overcrowding and shoaling fish whose size overwhelms our resources. One of the hardest things to learn is how to rein in the desire to add more fish. "Just one more species I've never seen before" has been the killer of many a group of fish.

Almost equally hard is the "that fish costs $25 each and is supposed to be in groups of 10" Prices aren't the fault of the fish, and they deserve the best conditions. There have been a lot of wondrous fish I haven't bought because I simply couldn't.

I find a formula I like. I calculate exactly how many fish of a certain size or of certain needs I can fit into my tank. I then grit my teeth and cut that number in half, ruthlessly. I don't care how I feel. I want longterm results.

 

[Naughts]

I've found this -

Thank you for the research, much appreciated. That link was corrupted but it led me to this, maybe this is it!

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