How do we know when our fish are happy/content/thriving?

Bruce Leyland-Jones

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For starters, I'll personally discount 'happy' and 'content', as these are human emotions and we're talking fish, but I know some will use that language, as that is how they understand the creatures they care for.

I'll also accept that all of us in here actually do want they best for our fish, even if we haven't a clue as to how to go about it. This thread is NOT intended to create judgement calls on people's apparent inability to make happy/content/thriving fish.

So we know that we cannot really communicate to any useful extent, or mutual benefit, with our charges...much as though some of us do genuinely believe they have a rapport.
So we have to use our observations of our fish, to ascertain their wellbeing.
Poorly fish are relatively easy to spot, as fish disease and parasites and general sickliness has been the bane of fishkeepers, ever since we started keeping them. As a consequence, a huge amount of research and effort has gone into poor fish health, it's diagnoses, its causes and its treatments.
It is tempted to believe that an absence of such means that the fish is well, content and thriving.

I think not.

We can have perfect physical and mental health and still not thrive. So it must be for fish.

Time and time again in this Forum I've seen the argument for meeting a fish's complex needs, in order for them to do way more than simply survive, or exist. Many of us have said that we believe our fish are thriving/have thrived, in spite of being in imperfect conditions.
As an example...my fish are always beautifully coloured, as they should be. Their behaviour is the same as that they exhibit when in the wild environment and they breed and raise young that appear to be totally healthy.
"Aaaah, but..." says someone. "The pH/water hardness/nitrate concentration/etc., isn't perfect for them, so they can't be thriving."
(Or should that be shouldn't be thriving? ;) ).

Any assessment on the wellbeing of our fish will be subjective, as long as it is within the parameters of good physical health.
I once knew someone who genuinely believed that her fish-babies loved her. She evidenced this by showing me how they all swam to the surface when she came into the room, to say 'Hello' and to pass on endearments! The reality was that the fish were always at the surface, gasping for air because of an over-stocked tank and poor oxygenation.

So how do YOU gauge the wellbeing of your fish?
For myself, I look for an absence of disease/parasitisation as a starting point.
Then I look for bright eyes and appropriately shiny and coloured scales/skin, with perky fins.
Then I'm looking for good movement and finally, for behaviour appropriate for an apparently healthy fish.
If all of the above are good and THEN there's breeding, then I think I must be doing something right...HOWEVER, given the artificiality of the environment in which the fish are kept, combined with a shortage of potentially suitable mates, I don't beat myself up if my fish don't breed.

So how do YOU gauge the wellbeing of your fish?
 

Byron

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Some very good observations/information here. I'll just point out a couple of things, to expand a bit.

No one can talk to a fish, and therefore, no one can possibly say with any degree of certainty that the fish are "fine" with "x" or whatever. Fish like all animals have a very strong will to survive and reproduce; fish that are swimming, eating and spawning may still be slowly dying. Fish have no choice but to "make the most" of the conditions we force upon them, or weaken and die.

The behaviour of the fish will (may) clue the aquarist in to the trouble, but usually only when it has become severe, chronic stress. Stress (which causes 90% of all fish disease in an aquarium) slowly weakens a fish. The effects of stress on fish are very complicated physiologically, and are often subtle. There may or may not be external signs discernible to us—it can continue for weeks and even months, sometimes up to the point when the fish just suddenly dies. The reasons for this are involved; it would bog this discussion down to go into this, but those who are interested in learning the reasons can check out my article here [it has links to the source evidence]:

The only assumption we can ever make that all is well with our fish is if we have provided them with what they need or "expect" to function at their best. Evolution has determined this through the genetic blueprint of each individual species. This does not mean that our failure to provide everything is going to kill the fish; but there is evidence that it does weaken it, and that is something we should try to avoid, not encourage. "It is inhumane to deprive any animal of an element it regards as critical to its well-being, and totally naive to expect normal behavior in its absence" [Dr. Paul Loiselle, acknowledged cichlid authority, from an article on providing the proper environment for fish].
 
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Bruce Leyland-Jones

Bruce Leyland-Jones

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No one can talk to a fish, and therefore, no one can possibly say with any degree of certainty that the fish are "fine" with "x" or whatever.
No one can talk to a fish, and therefore, no one can possibly say with any degree of certainty that the fish are not "fine" with "x" or whatever.
Fish like all animals have a very strong will to survive and reproduce; fish that are swimming, eating and spawning may still be slowly dying. Fish have no choice but to "make the most" of the conditions we force upon them, or weaken and die.

The behaviour of the fish will (may) clue the aquarist in to the trouble, but usually only when it has become severe, chronic stress. Stress (which causes 90% of all fish disease in an aquarium) slowly weakens a fish. The effects of stress on fish are very complicated physiologically, and are often subtle. There may or may not be external signs discernible to us—it can continue for weeks and even months, sometimes up to the point when the fish just suddenly dies. The reasons for this are involved; it would bog this discussion down to go into this, but those who are interested in learning the reasons can check out my article here [it has links to the source evidence]:

Fair points, although given that there's a 'bell curve' distribution of coping with each and every circumstance and factor, within any fish population, it would be extremely difficult to conduct valid controlled experiments to ascertain what is thriving and what is not.
The only assumption we can ever make that all is well with our fish is if we have provided them with what they need or "expect" to function at their best. Evolution has determined this through the genetic blueprint of each individual species. This does not mean that our failure to provide everything is going to kill the fish; but there is evidence that it does weaken it, and that is something we should try to avoid, not encourage. "It is inhumane to deprive any animal of an element it regards as critical to its well-being, and totally naive to expect normal behavior in its absence" [Dr. Paul Loiselle, acknowledged cichlid authority, from an article on providing the proper environment for fish].
I've always liked that quote, although, again, the phrase 'it regards as critical' can suggest more than fifty shades of off-white and paler black. ;) Science may be able to determine the probabilities of what benefits the fish, but might struggle to go further as we cannot talk to the fish. (Where's Aquaman when you need him?)

All that said, @Byron , you've yet to say how YOU determine whether or not your fish are thriving. ;)
 

Byron

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All that said, @Byron , you've yet to say how YOU determine whether or not your fish are thriving.

I don't determine this, because I also cannot talk to them, and I know without question that outward appearances can be very deceptive and misleading. In extreme cases one can see trouble, but not otherwise.

However, I do know that they are more likely going to thrive when and only when I provide them with what they expect/need in terms of their environment. This involves water parameters, habitat replicating (substrate, wood, rock, plants, whatever is needed), sufficient numbers of the species for shoaling fish, tankmate species that share all these values and are thus compatible but also peaceful, safe lighting levels.
 

xxBarneyxx

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Unless you are a marine biologist and are doing autopsy's on your fish when they die you will probably never be 100% sure. However in my opinion there are some key things that can point to if it is healthy or not.

The main things that I look out for:
  1. No disease's - Things like whitespot are always present in a tank. If a fish is stressed/unhealthy it will almost always get whitespot. Obviously some fish are more resistant then others but almost any time I have seen someone with whitespot problems they have either just bought a fish that had it or they have other tank issues.
  2. Healthy colour, healthy fins - Again a big tell that something is wrong. A LOT of fish will lose or change colour when under even small amounts of stress. Fin condition also tends to go down if things are not right for them.
  3. Behaviour - It's hard to say that I look for "natural" behavior because to be frank for the majority of fish we are keeping it is nowhere near their natural habitat. Take Cardinal tetras for example. We may get a "big"group of 30 or so but even then its not even close to how they live in the wild where they form shoals(schools?) of hundreds. However, unexpected aggression, changes in feeding behavior, hiding more than normal, swimming differently or in different parts of the tank can all pinpoint that there are problems.
  4. Lifespan - The captive lifespans of most of the fish we keep are well known by now. If your fish are living this long or longer with no health issues/diseases then IMO you probably did an ok job. Yes you can argue that just because a fish is living doesn't mean there isn't problems but I would argue that if there really is any problems then creatures as delicate as fish would have drastically reduced lifespans and regular health issues.
  5. Spawning, breeding, fry development - I love tetras, most of the tanks I have owned were mostly full of tetras. I have kept them in "bare" tanks with no live plants, tanks with low light live plants and no ferts/CO2 and tanks with high lights, plants, lots of ferts and C02. Guess which one I had more breeding happening in.. yeah the one that some people would consider "toxic"with the high ferts and CO2. I don't consider spawning itself to be an indicator of how healthy a fish is, and some species will never spawn in a home aquarium anyway. However if you have the same species of fish in two separate tanks with different setups and get more and healthier fry out of one of them then IMO its probably safe to assume that is the better option.
There are things to consider with the above though. One is genetics. Some captive bred fish are pretty inbred and as a result may have more issues then others. Some fish get injured/damaged during wild capture/transit which again can cause issues no matter how good your tank is. However if I can tick off the first 4 points above (and maybe 5 depending on species) then I consider my fish to be healthy.

You also have to think that in the wild the lifespan of a lot of these fish is a lot less then in captivity. Taking Cardinal tetras again. They lifespan in the wild is around a year. In fishtank its around 5 years. It doesn't mean you should mistreat them but they don't exactly have it easy in the wild either. So again if I can tick off the above I feel happy that I have given them a decent life.
 
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Bruce Leyland-Jones

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I don't determine this, because I also cannot talk to them, and I know without question that outward appearances can be very deceptive and misleading. In extreme cases one can see trouble, but not otherwise.

However, I do know that they are more likely going to thrive when and only when I provide them with what they expect/need in terms of their environment. This involves water parameters, habitat replicating (substrate, wood, rock, plants, whatever is needed), sufficient numbers of the species for shoaling fish, tankmate species that share all these values and are thus compatible but also peaceful, safe lighting levels.
You have said elsewhere that most of your fish are wild-caught. Does this approach of yours also apply to the farmed fish, whose 'perfect' water parameters and conditions may differ from those in the wild?
Whilst I can appreciate the reasons for replicating all natural conditions, there is a risk to be had in assuming that those conditions are actually optimal for the fish.
Evolution is tight with its energies and compromises are always made.
It is possible that, in an artificial environment, those compromises no longer need to be made.

I'm reminded of a short sci-fi story, where a human spacecraft crash landed on a miserable swamp planet.
The survivors were eventually rescued by an advanced alien species, who replicated exactly the miserable swamp planet's conditions, believing these to be the best for their new additions to their zoo.
 

xxBarneyxx

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sufficient numbers of the species for shoaling fish, tankmate species that share all these values and are thus compatible but also peaceful, safe lighting levels.
So you don't agree with keeping tetras that often live in groups of hundreds in the wild? Also if you are saying that you should match wild conditions as close as you possibly can then you should also include predators so that they have normal behavior for predator evasion?

Yes I'm taking it to extremes to make an example. The point is though you will never get anywhere close to matching their wild conditions. If you did they would die a lot quicker anyway. Do you think the majority of fish care if the plants and rocks in the tank are the same as they would have in their native habitat? Or do you think maybe all they care about is that they have the right amount of cover, or substrate, or whatever to be close enough for them to go through their normal behavior?

To me the fact that the captive lifespan for most fish is many times greater then their wild lifespan says that maybe trying to so specifically recreate wild conditions is not such a great idea all of the time.

Also I really hope this isn't coming across as becoming personal. I'm really enjoy debating this kind of thing and it is something that should be argued from all sides for the sake of the welfare of the animals we keep and the improvement of the hobby. If people didn't have this kind of conversation we would all still be doing fish in cycles using undergravel filters with overstocked tanks and flushing the fish alive anytime they had anything wrong with them.
 

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Whilst I can appreciate the reasons for replicating all natural conditions, there is a risk to be had in assuming that those conditions are actually optimal for the fish.
Evolution is tight with its energies and compromises are always made.
It is possible that, in an artificial environment, those compromises no longer need to be made.
Thanks that was a point I was trying to make but you did it much more eloquently then me :)
 

Myraan

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I would argue that nature, genetics, would determine what conditions a fish is happy in, therefore should treatment of wild caught and farm bred be much the same?

I sometimes wonder about people who buy discus farmed in hard water providing them with hard water because they are used to it. By definition such breeders will only have fish that survive well in conditions they may not be "happy" with. I may be wrong on this but I have yet to hear an anecdote of people killing their pet discus by keeping in soft acidic water with a nice shoal of cardinals. It is of course possible the hobby has whole populations of east european bred discus that have actually evolved to prefer hard water but I doubt it.

It is obvious the breeders will not care about long term suitability of their water - they just want to sell baby fish - so as long as their tap-water allows them to do that they have done their job.

Having said, every youtube channel will tell you to ignore hardness, just use whatever water you have.... look at the the fish I have they will say... some of them regularly kill their fish, but some of them are expert successful aquarists. Of course they would say ignore hardness, because if they didn't it would severely restrict what content they can produce unless they go over-board with the RO.
 

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I concur with most if not all of post #5 from @xxBarneyxx . As cardinal tetras were mentioned, I happen to have some interesting study evidence from a German study on this fish.

As for the lifespan, you are correct that this is an annual fish in the wild (so most now maintain), but it can live longer in the aquarium. But how long? Jacques Gery said over ten years if it is provided with the water parameters it needs.

Observations related to the study.

Origin: Amazon Basin, northern tributaries of the Rio Negro in Brazil and Peru [Brazilian form], Orinoco basin in Columbia and Venezuela [Columbian form]. Occurs in forest streams and creeks in slow or standing water, well shaded by vegetation and frequently having aquatic plants.

In their natural habitat cardinals are found in small slow-moving streams and still waters having a pH from 3.4 to 4.5, some locations a bit higher but rarely above 6 (the Rio Negro basin), and less than 1 degree of hardness. The Orinoco waters are acidic but ranges are higher. The water is always shaded by dense trees and either land vegetation or aquatic plants are always present. They congregate in groups amid aquatic plants, branches, or under overhanging land vegetation. They may be an annual fish in nature, only living one season due to shortages of food.

Programmed by nature over millions of years for such dimly-lit environments, the eyes of a fish are designed to capture the maximum amount of light. This allows the fish to have some degree of vision even in dimly-lit water. But when placed in brighter light, the fish will naturally look for cover in order to escape from that light. Aquarists can readily see this in the aquarium; many forest fish when given the option clearly prefer shaded areas. Baensch & Riehl (1987) called it a “light phobia” in characins. During an investigation reported by Geisler & Annibal (1987), repeated observations in the biotopes of Paracheirodon axelrodi (cardinal tetra) indicated that the fish avoided the more strongly lit parts of their favourite waters and that their habitat ends almost to the centimeter on the border between shade and sunshine.
 
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Bruce Leyland-Jones

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I would argue that nature, genetics, would determine what conditions a fish is happy in, therefore should treatment of wild caught and farm bred be much the same?

I sometimes wonder about people who buy discus farmed in hard water providing them with hard water because they are used to it. By definition such breeders will only have fish that survive well in conditions they may not be "happy" with. I may be wrong on this but I have yet to hear an anecdote of people killing their pet discus by keeping in soft acidic water with a nice shoal of cardinals. It is of course possible the hobby has whole populations of east european bred discus that have actually evolved to prefer hard water but I doubt it.

It is obvious the breeders will not care about long term suitability of their water - they just want to sell baby fish - so as long as their tap-water allows them to do that they have done their job.

Having said, every youtube channel will tell you to ignore hardness, just use whatever water you have.... look at the the fish I have they will say... some of them regularly kill their fish, but some of them are expert successful aquarists. Of course they would say ignore hardness, because if they didn't it would severely restrict what content they can produce unless they go over-board with the RO.
Actual genetics can change surprisingly quickly.
An oft-quoted example amongst biologists is the case of the Peppered Moth. This was originally pale and speckled, so as to be able to camouflage itself from predators on tree bark.
Then came the Industrial Revolution and the moth very, very quickly, (within a matter of decades), became darkly speckled, so as to be camouflaged against the now-sooted trees. (Their paler contemporaries all got eaten, because they all stuck out like sore thumbs).

EDIT for literacy.
 

Byron

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You have said elsewhere that most of your fish are wild-caught. Does this approach of yours also apply to the farmed fish, whose 'perfect' water parameters and conditions may differ from those in the wild?
Whilst I can appreciate the reasons for replicating all natural conditions, there is a risk to be had in assuming that those conditions are actually optimal for the fish.
Evolution is tight with its energies and compromises are always made.
It is possible that, in an artificial environment, those compromises no longer need to be made.

I'm reminded of a short sci-fi story, where a human spacecraft crash landed on a miserable swamp planet.
The survivors were eventually rescued by an advanced alien species, who replicated exactly the miserable swamp planet's conditions, believing these to be the best for their new additions to their zoo.

I do not agree with most of this. Commercially-raised fish are no t an exception, but we could get into a huge discussion just over this, so I'll leave it.

As for environmental conditions being optimal, yes they are, and there is no reason to think otherwise. You cannot change what is inherent in the species genetic blueprint, and that is what we are talking about here, providing what the species "expects" because they know no other. This is dealt with in the Manual of Fish Health, by five eminent biologists. I am not goinng to argue with them, they know more than I do.
 

Byron

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Actual genetics can change surprisingly quickly.
An oft-quoted example amongst biologists is the case of the Peppered Moth. This was originally pale and speckled, so as to be able to camouflage itself on tree bark.
Then came the Industrial Revolution and the moth very, very quickly became darkly speckled, so as to be camouflaged against the sooted trees. (Their paler contemporaries all got eathen, because they all stuck out like sore thumbs).

This is true, but not relevant to fish in terms of time. There are moths today in the Amazon that evolve into a new species within one year, regularly. The rapid lifecycle is likely one reason why this happens, but this is not the case with fish. I am not aware of an qualified biologist suggesting a species we keep has evolved in a couple years.
 

Myraan

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I agree, but the reason I doubt we have discus evolved to hard water, which I suspect is less trivial than a colour morph, is the lack of anecdotes of aquarists killing their new discus with soft water habitats.

Please correct me if that is wrong - as it would be quite interesting if that's the case.
 

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As a former teacher, I have an internal rubric where I score how happy I think my fish are:

1. Is the quality of the water good? (ie. temperature, low-0 nitrates, 0 ammonia/nitrites)
2. Is the pH/kH/gH within a range that is either naturally occurring and/or due to commercial breeding is likely suitable?
3. Is the tank decorated in a way that would allow the fish to feel secure and/or behave naturally
3. Are there any signs of aggression?
4. Does the fishes behavior match what is expected for it's species?
5. Does it's color reflect what it should be?
6. Am I able to provide with sufficient space?
7. Am I able to provider a diverse, nutrient dense diet for them?


I was there was really a way to know for sure if they are happy and thriving!
 

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