are fish just not lasting as long as they use to???

[TwoTankAmin]

I should have mentioned this in my post above. In order to do a dry rainy season for my Xingu plecos I basically took three months to raise the tank water temp to 92F and TDS to the 175 ppm range at the end of the 3 month build up of the dry season. I chose that range because my tap would serve as the rainy season and it has a TDS of 83 ppm, I would do the onset of the rainy season to conincide with on oncoming storm to also gain the advantage of the barometric pressure drop.

To do the onset of the rainy I would do a large water change- about 60% with my tap water at about 75F. I did not do this slowly either because in the wild the rains combined with the melt water from the Andes is pretty cool. I would unplug the heater and reset it to 80F and at the end of the water change the tank temp was about 80.

Within the next 24-36 hourse I repeated this but with a bit less water changed. I left the heater plugged in at about 82. The water would drop into the mid 70s before the heater brought it back to 82. It did not kill the fish. it did not kill the fry that might still be in the breeder tank either.

I have to confess that I did not have to do this dry/rainy very often. I am very fortunate in how many of my fish bred in my well water with no helo or encouragnement from me. This went beyond plecos to include angels, discus, corys, Cherry barbs, several danios, a couple of Pseudomugil rainbows, Pseudocrenilabrus nicholsi and I even got surprise fry from some threadfin rainbows I had temporarily parked in a bristlenose grow tank. I usually tell people that my well water contains a natural fish aphrodisiac. It also seems to work for my Neocaridina davidi both red and blue varieties.

Here is another good story from my tanks. I had a 40B withch held a pair of adult discus, a school of rummy nose corys and 5 Hypancistrus L450 I was growing out to spawn. I was working on another tank in the room and I glanced over at thr 40 and saw one of the discus stuck to the intake of an Aquaclear. I knew that ws not right and I went over to the tank. When I lifted the lid I caould almost feel the steam coming up. the water was about 105F. The other dead discus was starting to rot at the surface yunder the floating plants. Also imiced in with the floating plants were mush balls which used to be the tetras. The cause was one of the two heaters in the tank got stuck full on.

But when I looked into the caves I had put in for the L450s, all of them were hunkered down but very much alive. I immediately removed the dead fish and di a large water change to get the temp down into the 80s. two weeks later the L450s spawned for the first time. I sold the breeding group about 10 years later along wwith the most recent fry from them.

I did have a similar geater failure some years later which wiped out my original breeding group of 10 L236 along with about 30 or so fry. The bellies of the adults had exploded om several of them. Fortunately I had sent 26 larged offspiring to a friend to sell and i had another 23 in a grow tank. I was able to create a new breeding group from those 23 offsping. This second boiling is what started me buying heater controllers for all my pleco breeding tanks.

 

[seangee]

As long as I've been keeping any sort of exotic creature in captivity, seasonal changes in temperature, humidity, day/night length etc. has been a part of their regime. Why are fish any different?

In a lot of equatorial habitats, the temperature is stable year round.

And for most of us it is not, but you are correct and the same applies to daylight hours. The only seasonal differences are wet and dry.
I'm more relaxed about temps than most. In winter I have a 2c (4F) variance between my heater on and off temps. In summer the heaters are off - even though I live in England which (as everyone knows) is always wet and cold
But in summer the fluctations are larger. Yesterday when I started work the tanks were over 28. After a full day of aircon they were down to under 25. This morning by 6 am they had drifted back up to 27, and the aircon is on again. It will be on again tomorrow, but by the end of the weekend I expect my tanks to be over 30.
So my fish do have a summer and a winter, simply because I have less control over their environment in summer.

 

[Magnum Man]

I get why we change water continually... but in the wilds, while temps may remain close, the water must change between rainy season, and dry season, that most areas would experience... I would think the actual falling rain would be cooler, though as it cascades over the land and vegetation, it would warm to ambient temperature but would think this also causes a Ph and solids change... but these changes are natural, and not likely to effect the fish's life span, unless there is increased pollutants that come with the rain, from industrial or agricultural chemicals...

I still suspect something else... 30-40 years ago, I think the normal, was just to replace the water that evaporated from our tanks... I personally started something ( water changes ) on my own, as we had no internet, and no local club, when I discovered, that the jungle of house plants we maintained at the time, grew leaps and bounds better, with fish tank water, and I actually began to vacuum tanks, all this, not for the fish's benefit, but to get more good stuff for the plants...

in hind sight, my fresh water tanks flourished, and my salt water tanks always struggled, as I wasn't changing water in the salt tanks, because I couldn't use that for the house plants, like I did the fresh water... that continued, until I moved to a place that I couldn't have all the plants....

but, yesterday I changed a 100 gallons of RO water through my tanks... back when I was watering plants with tank water, I had 7-8 milk crates, that each held 4 plastic one gallon jugs, so at most, I was changing 30 gallons a week, so no where near the 30%, twice a week, I'm doing now... maybe my memory is failing, and it's a case of "thegood old days" syndrome, but my tanks, and fish were, what I remember, better than they are today, using filtered water, and a much increased water change schedule...

it certainly must be the fish, as I throw much more money into the hobby now, all the new equipment is better, right

 

[GaryE]

There's an awful lot we can't control. Temperature can be one, and water hardness can be another. Yes, they can be controlled with technology and fancy set ups, but 99.999999% of us are in this for fun and don't have the money to build dedicated spaces like that. I'm ahead of most of us by having a large room for fish, but my tech is running water, a drain and walls. To make it a climate controlled paradise would have cost more than I could come up with.

So the fish are subject to weird things. Lighting periods change here, but not there. Seasons happen here, but not there. There's no rainy/dry season division. The water in tanks is always dirty. I only do 30% changes once a week. The water I waded in in dry season Gabon was pristine. There was probably a fish every 1000 gallons. The rains were about to dilute that by a couple of feet, making it even cleaner, chemically.

The Corydoras group are the fish whose seasonal rhythms get the most respect. Breeders will stop water changes for a couple of weeks, let conditions get bad, then flood the tank with cooler imitation rain to start them breeding. The arrival of hope with fresh water fires up their breeding cycle, and it very often works.

A lot of new aquarists, or father fish afficionados manipulate another feature of the Amazon's seasons. As the water evaporates in the season of no rain, oxbow lakes form out of dried riverbeds, concentrating the fish. Each pond is an island of water, evaporating as the sun heats it up. The fish go into a low energy type of suspended animation, with lower metabolic rates and slowness in the crowding. The arrival of the rains saves them, or rather saves some of them if it arrives in time. In no water change, low water flow tanks, the oxbow goes on forever.

The most extreme is annual killies, whose life cycle is often based on huge swampy lands that support large populations of these tiny beauties, but which become meadows in the dry season. The adults die, but not before they've laid eggs in the clay/soil, which in some places bakes to a hardened crust. With the return of the rain comes the return of the fish. The eggs can go into a diapause, a suspended state that runs from a few weeks for some species, all the way to six months or more.

Another system people have used for a long time is the manipulation of water levels. Some fish will only breed in a very shallow tank. That's why I've started making a few undergravel filters, because their pipes can be cut to function and filter very shallow tanks.

There is an entire set of ideas, tried and true, that breeders of fish know. Keepers usually don't care, but breeding calls for more awareness. Some people fake thunderstorms with lighting. A certain guy I know, one who tends to make typos in his messages, has been known to dart out when thunder rumbles in the distance so he can get a water change in as the storm hits. It sounds obsessive, and it probably is, but it works.