outdoor stock tanks...successes and failures

[jjohnwm]

Weird summer this year. We had a bit of a late spring...and then a week or so of blistering (by our standards) temperatures approaching 90F...and then it cooled down again. But now, after a torrential rainstorm about a week back...we just had another one! The yard flooded to the point where the surface area of my pond expanded from roughly 175 square feet to something like 1800 square feet! As the pond overflowed its boundaries, several of my Goldfish went on exploratory missions that had them swimming blithely across the lawn many yards from the pond itself. I've had a couple of utility pumps evacuating water from the yard and out into the pasture.

The Duckweed on all my stock tanks is 90% gone, simply drained away as the rain overflowed the containers. The fish in the stock tanks all look good; the Gymnos are shepherding schools of fry around; the Dimerus cichlids have just finished laying eggs, hatching them, and then almost immediately eating all the fry (3rd or 4th year of this kind of crappy parenting); Paradise Fish bubblenests were destroyed or washed away by the rain; new Swordtail, Ameca, Jordanella and Corydoras fry visible in their respective containers. This year I devoted one stock tank to Jenynsia onca, one of the so-called One-sided Livebearers, and the fish seem to be doing well but no fry have been seen.

The inground pond was treated to some supplemental aeration this year. An ill-conceived experiment with a cheapo online-purchased solar pump proved, once again, that you get what you pay for...if you're lucky. This year, with my Goldfish much larger and especially with my HiFin Myxocyprinus sucker in the pond, I added a poor-man's aerator created by the simple expedient of setting up a 55-gallon plastic drum on the little deck next to the pond, keeping it filled with cool water from the hose and allowing it to dribble down into the pond from a valve-controlled bulkhead drilled near the bottom of the barrel.

This seemed to benefit the Myxocyprinus, who just seemed perkier and faster-moving after it was set up. Finally, just before the rain hit, I ran a buried airline out to the pond from my basement air pump. This seems to work just as well as the water drum, is essentially invisible, and best of all it doesn't sound like a moose is pissing into the water 24/7. That noisy aspect of the water barrel became quite irritating quite quickly.

No more herons; mylar whirling windmills and a motion-activated sprinkler system help keep them away, and of course the fact that my dog Duke caught and killed one in the act of pilfering fish helped as well. I think I have lost a grand total of one Goldfish this season, and that's to the one bird that Duke "disciplined".

Figures. After several decades I have my indoor fishkeeping pretty nicely honed in terms of minimizing hard work while still allowing easy, frequent and large water changes. No need for buckets, siphons and other PITA paraphernalia, except if I want to do an occasional spot clean here and there. Rube Goldberg DIY solutions everywhere you look for things like filtration, lighting, heating, plumbing, storage...and now I spend all my time tinkering and fiddling and farting around with outdoor tanks all summer long...

 

[duanes]

When I lived in Wisconsin I used those shallow preforms most people would toss (because in reality they were really too small for fish) to grow what appeared like) spent brine shrimp egg cuultures to adults.
I was always amazed at tossing out a bunch of old eggs would yield, after a few weeks in a sunny yard, and how little aberrent salinites mattered.

 

[jjohnwm]

When I lived in Wisconsin I used those shallow preforms most people would toss (because in reality they were really too small for fish) to grow what appeared like) spent brine shrimp egg cuultures to adults.
I was always amazed at tossing out a bunch of old eggs would yield, after a few weeks in a sunny yard, and how little aberrent salinites mattered.

View attachment 1577763View attachment 1577764

I keep saying I want to experiment with this idea, ever since reading a post you made about it awhile back. I was amazed at your success level and with the minimal cost and effort expended. I have a rather flimsy rigid kiddie wading pool that seems ideal for this experiment. I'm doing it today!

 

[jjohnwm]

My outdoor stock tanks and pond are a mess this year. We had not one but two massive rainstorms which completely overflowed all of them, resulting in the loss of almost all of my duckweed. Combined with an overenthusiastic trimming last year of the tree branches that provided some shade, this has resulted in the dreaded green water in all but 3 of these tanks.

Here's a view of the inground pond. This pond has not had green water for at least the past 5 or 6 years, but now it's horrible. The Goldies are doing very well, with the largest of them approaching 9 inches in length. And even though they are several years old, some of them are still changing colour; one in particular started life as a wild-form green/bronze fish who then turned dark brown above and almost whitish on his bottom half, with the two colour sharply delineated. He remained like that for a couple years, then last winter indoors he abruptly became an almost all-black fish with a bright orange head and lower parts. And now, since going outside this past spring, he is rapidly losing all that black and now appears that he may become a classic all-orange goldfish. Other specimens are exhibiting similarly extreme colour changes as well...not that you can see them in this pea soup. I still see the HiFin Banded Sucker off and on; he's looking good, and industriously cleaning the algae off a large floating stump.


Another green water problem child is one of the stock tanks. This one contains a half-dozen adult Corydoras (or whatever they're calling them this week...) paleatus, along with a similar number of Jenynsia onca "One-sided Livebearers". These fish didn't seem interested in breeding while downstairs, but I am now seeing good numbers of roughly half-inch fry in this stocktank. Both fry and adults are quite surface-oriented and are absolute speedsters, very quick and active.


One of the smaller stock tanks (150 gallons, I think?) contains only 2 pairs of Macropodus opercularis Paradisefish. Both males have built bubblenests in the surface vegetation that has continued to shade this tank and keep it clear. It's heavily planted with Cyperus Dwarf Papyrus which I overwinter as a couple of large adult plants in the basement and then place in the stock tanks in springtime. The tall stalks droop down towards the water surface, and when the florette of leaves comes in contact with the water a new plant forms. The stalks of the adult plant are long enough that they droop into the stocktanks on either side of the one containing the adult plant. So by midsummer I have about 15 new plantlets, complete with extensive root systems, spread out over three adjacent stocktanks.



Several of the stocktanks this year are hosting Grey Tree Frog tadpoles. These guys are weird; lots of them some years, none others. This is a good year.



And, finally...I have reached the limit of my patience with my Cichlasoma dimerus. Last year, the dominant male killed his subdominant rival. This year, he...or perhaps his equally psychotic belle... has beaten the subdominant female so badly that her survival odds look like 50/50. And, as they have done for the past several years, they have spawned, hatched fry, tended to them for a few days...and then killed every last one of them. I'm done with them; they will live out their days in my basement tank. If they want to raise young and then kill them, they will be free to do so, but they won't be getting their very own stocktank all summer long as they have up till now. The dang things are only 5-6 inches long...and yet three of them can't live peacefully in a 6-foot diameter tank? I'll try to find them a home with somebody else; otherwise, they will go for a siesta in my freezer and then wind up on an 8/0 circle hook as part of a catfish rig.

 

[jjohnwm]

So, in various tanks/stocktanks, I have leeches, fishing spiders, predaceous diving beetles, water scorpions, giant water bugs, assorted tadpole species, dragonfly larvae and any number of smaller invertebrate species quietly going about the business of survival. None of these are particularly troublesome or even unwanted, as long as they don't get out of control. If I lose the occasional fish...adult or fry...to some interesting predator, I consider it part of the cost of doing business in the great outdoors. Just the other day I finally witnessed for the first time a Fishing Spider capture and devour a small Swordtail. Not a wonderful experience for the fish, but a fantastic sighting for me. This year, none of the above-mentioned visitors has had a significant population explosion, so their depredations have been very acceptable. In past years, we have occasionally gotten way too many of this or that species of predatory aquatic insect, and I would do my best to curtail their numbers as much as possible; that hasn't been a concern this year.

It's been a fantastic year for several frog species. We've had record numbers of Wood Frogs, Boreal Chorus frogs, Grey Treefrogs and even some Leopard Frogs produced in various stocktanks or in the main inground pond. I like frogs; they generally don't bother the fish, they eat lots of bugs, and the biggest complaint I have is that they make mowing the grass a little stressful as I jig left and right and back again with the mower trying to avoid running over the tiny froglets on the lawn.

But there are a couple of species of...let's call them invaders...that have somehow managed to turn up in just about every outdoor water body in the yard, and which range from "Hmmm...that's interesting..." all the way to "WTF are you doing in there?!?"

I'll admit, it's my fault entirely that they have spread so completely through my outdoor waters. I freely move big handfuls of Hornwort, Najas, Duckweed and even Hair Algae from one container to the next, and that's allowed these critters to spread like wildfire.

What are these offenders? Goldfish...and Gymnogeophagus rhabdotus cichlids! The inground pond is, as always, full of Goldfish of every size, as intended. But of seven stock tanks, six (!) have G.rhabdotus fry; only one is supposed to have them! And five have Goldfish, which aren't supposed to be in any of them!

The rhabdotus are okay; they're all fairly small and they don't go looking for trouble. But the Goldfish...well, there are at least 2 of them in my Ameca splendens tank, and both have achieved a size that could potentially pose a threat to a newborn Ameca. And the single Goldie in the Green Swordtail tank is certainly gobbling up fry in there, although the numbers are so much higher that it hardly matters.

My Jordanella Flagfish stocktank is thankfully free of Goldies...as far as I know...which is a good thing since they breed fairly slowly. And of course the dimerus cichlids are so insistent upon eating every single one of their own progeny that they likely eat other species as well just in case.

Of course, there is a very simple solution for these infestations. All I need to do is decide that I want to breed as many Goldies and Gymnos as possible. That resolution will produce an immediate disturbance in The Force...which will in turn curtail all reproductive activity at once.

 

[jjohnwm]

Nothing interesting to report here; I'm just using this thread as a notebook to keep my own observations and records of my stocktanks.

I've spent the past three days emptying/cleaning/prepping my 7 stocktanks for winter storage. We have had a succession of cool nights, in the 4C range, and combined with coolish days that are growing shorter and shorter, the tanks have not risen above roughly 15C for about a week. It's early, but I decided to bring the fish indoors. It's been the shortest outdoor fish season for me since moving here; 15 weeks in total.

The Jordanella floridae Flagfish had a fairly successful year, at least for them. I started with 10 adults and ended the season with 9 adults and 25-30 fry. All of the fry were in the 3/8-1/2 inch range, suggesting that after the initial spawning shortly after they went out, there was no attempt at a second spawn.

Green Swordtails bred like mice, as always. Started with a dozen, have roughly 150 in a variety of sizes. No surprises here.

Jenynsia onca (One-sided Livebearer) were a new species for me; I had 2 males and 4 females. They spent last winter indoors, were very active and fast-moving, excellent feeders on frozen and freeze-dried, not so much on flakes or dry food. Once outside, they did well and produced a total of perhaps 40 fry. The fry were large, reminiscent of Ameca or other Goodeids. They're in a bin down in the basement; looking forward to installing them in a tank that allows good observation.

The Jenynsia shared their tank with a half-dozen Corydoras paleatus; sorry, not looking up the new name right now. These were installed outdoors in the 3/4 - 1 inch size range, and are all at least 1.5 inches now. They are the most spectacularly colourful C.paleatus I've ever owned, and I have had the species for many years, but they absolutely blossom outdoors. Sadly, although I spotted some eggs outdoors, they appear not to have produced any fry that survived. Not sure if the Jenynsia are responsible, but they are very fast and very aggressive feeders, so...?

Next tank was Ameca splendens. I moved away from these fish a few years back but found some recently and picked them up. 2 male and 4 female adults produced 17 fry, born at a size of roughly a half-inch and looking great. The males lack the black/yellow colouration on the caudal fin of my previous A.splendens, and I am wondering if they have been misidentified by the seller. Will try to get some pics when they are settled indoors.

Paradisefish (Macropodus opercularis) were in the next tank; 2 pairs, with no other inhabitants, in a stocktank of over 100 gallons, heavily overgrown with plants. Lots of courting and displaying and chasing and sparring; several occasions of fairly large bubblenests jealously guarded by males...and no fry ever seen. No idea what happened; hard to believe that none of the eggs hatched, but also tough to swallow the notion that all were eaten by the parents. Several nests were destroyed when heavy rainstorms overflowed the tanks and skimmed off much of the surface vegetation, but still...?

Cichlasome dimerus? I've grown to hate these fish; not the species, but these individual fish! Started with a half-dozen a few years ago; when they matured, the males (3) fought and killed each other each summer when temperatures rose. When the dominant male was the only one left, he and his girlfriend proceeded to wipe out the other 2 females. Finally, now, several years down the road...he decided to kill his mate. They produced numerous spawns for the past few summers, hatched most of them...and then ate every last one of his progeny. For the past couple summers, they have had 6-foot diameter stock tanks all to themselves, and aside from a great deal of frustration...I have nothing to show for it. The male is going to live with a couple from whom I got my Chinese HiFin Shark; he deserves whatever happens to him.

Gymngeophagus rhabdotus long ago replaced the dimerus in my affections. I love these little guys; beautiful colour, perky cichlid behaviour but not homicidal maniacs, breed like it's a mission. I put about 20 into my largest stocktank, almost 8 feet in diameter. I pulled out easily 200 fry of various sizes.

I suppose that most or all of these numbers seem unimpressive to people who toil to maximize productivity; separating fry from adults to raise separately, protecting them from predation by other fish and/or insects, perhaps some "power-feeding" to increase growth rates. I don't do any of that stuff; the fish, both adults and fry, are left to their own devices to survive as best possible. I feed only lightly, forcing the fish to find much of their own sustenance. Even after the fry hatch, my feeding is pretty sparse. So I expect...and get...a lot of infant mortality, and won't do anything to change that. Even as it is, I will likely use a large percentage of most of these fish as feeders; simply can't and don't want to try raising them all.

The inground Goldfish pond will remain untouched for at least another month.

Two pics. First, my new favourite pond plant: Dwarf Papyrus. It's not very dwarfish; can easily grow 4 feet or taller out of the water, still much smaller than the tree-like full-size variety. I started with one small plant; it grew into a large luxurious bundle, and as each of the long stems dipped down and contacted the water, a new plant would form from the rosette of leaves at the tip. This pic shows the original bundle, already trimmed down to a manageable size for the basement, along with 30 new plants, all with very full and extensive root systems.


And here's a Goldfish that somehow slipped into the Ameca stocktank back around June 1. I noticed the then-1-inch Goldie when I poured the fish into the stocktank. Tried a couple times to snag it through the summer without luck. Look at the dang thing now! I'm pretty sure this guy likely gulped down a few new-born Amecas once it got this big. Why couldn't it have been in the Swordtail or perhaps G.rhabdotus tank? I have far more of those and wouldn't miss a few more or less.

 

[danotaylor]

Seems to me to be a noteworthy achievement in a 15 week season! Well done mate
Definitely would love to grow some of the dwarf papyrus if I ever get an outdoor pond established!

 

[jjohnwm]

Definitely would love to grow some of the dwarf papyrus if I ever get an outdoor pond established!

It's a wonderful plant, and it survives quite handily for 8 months or more in my basement fishroom if provided with decent light. Now that I have like 25 small new plants, I will try keeping some indoors permanently to see how they do.