Prepping Tank for Betta
No, even though I’ve never seen them to be all that accurate myself (but it may just have been the particular brand). What I’m saying is that there are some hobbyists who feel they do not need to have a thermometer when using a calibrated-setting heater. This is a false assumption since anything can go wrong with any heater at any time — and a regular habit of monitoring your thermometer reading may save your fish from disaster.
It would seem normal, in the least, for a cold-blooded animal evolved in somewhat warmer temperatures to appear somewhat sluggish as you describe at those lower temperatures. Prolonged, it could have adverse effects, but I note you do turn the heat on when the temperature really dips. Not the most ideal method of maintaining the fish as those dips can be out of or near the extremes of the fish’s normal range.
As it appears you might be suggesting, fish in the wild do not always have “perfect” temperatures all the time, and the temperature of their environment can and will vary throughout the seasons — even varying according to the strata of the water at any given time during the day. Because of the fluctuation of temperatures at differring levels, the fish CAN (but not NEED) to be subjected to these variations IF it chooses to do so. In an aquarium, the fish does not have any option to swim in any other temperature except that of its enclosed environment — which can vary substantially faster than the average volume of a stream, even if that stream’s temperature may be somewhat stratified. As a moving body of water, a stream tends to homogenize somewhat. Ponds and/or lakes on the other hand do not mix aas readily except during the periods of storm when the layers get churned, and then that’s a slow process.
With this, by your questioning whether fish have perfect temperatures all the time (and you may be meaning, do these temperature extremes they experience ever vary beyond that range in which they can tolerate), I’m assuming you may be referring to temperatures they’ve never previously experienced as a species. The answer to this is no, as a fish (a species) from any given area has evolved over time within all the temperature extremes that particular area has experienced over the time period it has taken to evolved that species. In effect, the species has gone through all the temperature swings that has ever occurred in their native environment during the time it took that species to evolve; for this species to have survived means that the coldest their environment has ever gotten during the evolution of this species has not yet been beyond their capabilities to endure.
If by chance their temperature in the wild had ever gotten below the point of their survival, they would not be here. Likewise, the present range of temperature in the wild may have wiped out other species which are no longer extant, if that species could not tolerate whatever extreme that was. A very similar species may have been involved, which perished, and this surviving species may well be a mutation of the perished one, allowing it to survive at 65 o, or 63 o or 60 o (or 68 o), whichever was its lowest temperature during the time of its long evolution. The extreme of an animal’s range of endurance, although tolerable, is never the ideal.
One thing that is not being taken into consideration is the vast difference between the wild environment and that of the enclosed ecosystem of the aquarium where the fish are at the mercy of any pathogens co-existing with it (”captive” has many consequences). Ray
Category: Philippines Internet Koi Society
