Shout Out: Smallest Tank, Biggest Tang and YOU!

[Timfish]

Oh! The old "happy fish" observation! Here is an editorial I wrote on that topic. TLDR - the last paragraph is my definition:

Happy fish?


Driving in to work one morning, with a half a pot of strong coffee boiling through my veins, I got to pondering – when you hear somebody say, "you need to do X,Y,Z in order to keep your fish happy" or "your fish cannot be happy in that size tank" what do they really mean? Are they using the word "happy" in place of "healthy" or "proper well-being"? Or do they really mean to imply that true happiness can be identified and then quantified in fish?

I may use that term myself – "Man, that fish sure is unhappy." to identify a fish being bullied by a tankmate. What I really mean is "That fish has an ongoing territorial conflict with a tankmate, it is exhibiting a depressed demeanor and its well-being is compromised. If something isn’t done to change the situation, that fish’s health will be affected, eventually to the point of morbidity followed by mortality". It is just faster (but far less precise) to use the word "unhappy".

On the other hand, an animal rights advocate may look at a single fish in a tank and exclaim, "how unhappy that fish must be, all alone in that small tank". I suspect that in these cases, they mean not the fish’s well-being and health, but that it is truly unhappy in the mammal paradigm of how the word is generally used in English.

Now don't get me wrong, I don’t have a problem that some people do with semantics – as long as their intent is clear. Same thing could be the case with "happiness", I'm content to let the term ride unless I think the people really mean "smiley face" happy, as in "the opposite of sad" when talking about fish.

However, if for example, one of the "tang police" say, "hepatus tangs need at least a 150 gallon tank in order to be happy" they are not using the word in place of "healthy" if that same tang can be kept healthy and problem free, long term, in a 75 gallon tank. They are then adding an extra layer to the definition, one that cannot be measured or quantified. I do have a problem with that, it is misleading or ambiguous at best.

I’m not condoning keeping fish in overly small aquariums, I’m just opining that you cannot formulate tank size requirements based on intangibles such as the "happiness" of a fish. If your opinion is that this example fish is so much happier in the 150 gallon than the 75 gallon, that the smaller tank becomes a non-starter, then the fish would be whole orders of magnitude "happier" in the wild, and shouldn’t be kept in an aquarium at all.

Since 1985, I have been collecting fish respiration rate data as a means to try and identify stress in captive fishes. Certainly, I discovered that stressed fish respire at a higher rate (with temperature, species, and size all being factored in). I then collected baseline data from wild fishes in the Bahamas and the Galapagos. My hypothesis was that fish from the wild would respire at the best, most stress-free rate. Funny thing – almost all of those fishes respired faster than captive fish. It turns out that swimming against currents and waves, sculling around looking for food and out-swimming predators were all combining to cause these fish to be MORE physically stressed than captive fish by this measure. Are they less happy then?

So here is my working definition of "appropriate aquarium husbandry", and I say this equates to "happy" for a captive fish:


If the fish shows no signs of chronic disease or abnormality, exhibits normal feeding and reproductive behaviors and most importantly, exhibits a normal lifespan compared to that of wild counterparts (minus the predation that wild fish incur of course!), then there is no other metric we can use to determine if a certain suite of husbandry techniques are suitable or not.

Yeah, it's not the first time I've had someone tell me fish swimming around normally in a system are unhappy. But questioning them they can't describe any behavior that points to them being unhappy.

When I started I remembered stuff in hte news back in the 70's about zoos changing to stop repeditive behaviors in animals and that was one thing I'd look for. A few years ago I stumbled across the link I posted above on "steriotypy" behavior that describes it fairly well for the layman. I've also seen fish that show prefferences to individuals and pay a lot of attention to what's going on around their tank. So in addition to your definition I also look for fish that are interactive, demonstrate curiosity (hold your finger against the glass and it shouldn't take too long for fish to check it out), and swim leasurely around without repeditive or spastic behavior.

 

[Jay Hemdal]

Yeah, it's not the first time I've had someone tell me fish swimming around normally in a system are unhappy. But questioning them they can't describe any behavior that points to them being unhappy.

When I started I remembered stuff in hte news back in the 70's about zoos changing to stop repeditive behaviors in animals and that was one thing I'd look for. A few years ago I stumbled across the link I posted above on "steriotypy" behavior that describes it fairly well for the layman. I've also seen fish that show prefferences to individuals and pay a lot of attention to what's going on around their tank. So in addition to your definition I also look for fish that are interactive, demonstrate curiosity (hold your finger against the glass and it shouldn't take too long for fish to check it out), and swim leasurely around without repeditive or spastic behavior.

Yes - stereotypy can indicate a wellbeing issue in mammals and birds. It is less clear how much of an issue it is for lower animals. I had a LN butterflyfish that would swim in a pattern in the tank about 80% of the time: up a wall, do a backflip, swim upside down across the surface, dive down, swim across the bottom, then repeat. On the other hand - let's say there are a shoal of fish in a cylinder tank - how can you tell if they are exhibiting stereotypy (grin).
I had a large sweetlips in a cylinder tank. It swam in circles and would bump its eye with each pass. Its eye became inflamed and we moved it to a different system. In that case, the stereotypy manifested itself with a physical problem.

Jay

 

[Timfish]

Yes - stereotypy can indicate a wellbeing issue in mammals and birds. It is less clear how much of an issue it is for lower animals. I had a LN butterflyfish that would swim in a pattern in the tank about 80% of the time: up a wall, do a backflip, swim upside down across the surface, dive down, swim across the bottom, then repeat. On the other hand - let's say there are a shoal of fish in a cylinder tank - how can you tell if they are exhibiting stereotypy (grin).
I had a large sweetlips in a cylinder tank. It swam in circles and would bump its eye with each pass. Its eye became inflamed and we moved it to a different system. In that case, the stereotypy manifested itself with a physical problem.

Jay

Fortunately steriotypy has been very minimal in my experince over the years. There are times also when trying to catch a fish would have caused a lot of damage to corals so teh decision was to just leave it. The sailfin tang in hte 2 videos I linked was an unusual example though. It didn't display any repeditive behavior in the tank it grew up in. Shortly after rehoming to the 240 it started swiming rapidly from end to end, would hit the glass right at the water line, loop around and go to the other end. One variable that stuck out was in it's previous tank there was an autofeeder that dropped food into the return output so it was broadcast over a large area but in this 240 it was fed a faily large amount just once or twice a day. Adding 2 autofeeders that dropped small amounts 8 times a day stopped the constant swimming from end to end and made for a more leasurely system overall.