spawning fish with rain water

[Flareside]

Anybody ever try using rainwater to spawn their fish?
Some of the theories I have read claim that in the wild, fish will often spawn after a heavy rain. The heavy rain is supposedly similar to a water change with fresh and differing water chemistry. I had hoped for rain from a violent thunderstorm, but we didnt get any of that. I dont know if this theory is real or internet banter, but I decided to try it today.
In a 125gal, I have a couple of groups of wild caught fish I bought from Atlantis. Cyps, calvus, Nasuta's, and some tank raised foai. I changed 20 gallons of old water out and added four 5 gal pails of water from the heavy rain we finally got today in CT. Tank was around 8.2 for a ph and the rain water is around 7.4/7.6. I guess only time will tell.

Just wondering if anyone has ever tried this method

[fischfan13]

Les, do you have to use the water within a day or two?
Can you leave it in a vat for a long period of time?
Does the ph change after time in the vat?

Sounds like a pretty neat experiment.:ty:

[jroo99]

Sounds like a pretty neat experiment.:ty:[/QUOTE]

Sounds like one for "fischkid".

[Flareside]

to be honest with you Bill, I have no idea. I was just looking to find something new and interesting to post on the board and I got an idea and ran with it.

Im sure when Ed gets finished putting on Barry Manilow for his laying chickens, he will research the h#ll out of this topic. Melinda can probably chime in with more hours of chemistry knowledge of the top her head than I was awake for in class.

PH does fluctuate in tanks as well as pools, so Im sure that as the water ages, the properties will change as well. Im not even 100% sure what I did was safe and thats why I only changed 1/5th of the water.

I did the change 5 hours ago and as I type this, the foai has jet black fins and some color on his body. Looks like he is starting to build a nest. (I have never seen anything but dull silver before on these guys. I was going to unload them at NEC's auction last weekend because they werent coloring up). Even if they dont spawn, I am psyched to see some color! I was going to feed them some different stuff to condition them to spawn, but I was hoping to avoid introducing a variable which would dilute my experiment. Another words- was it the rain water that got them in the mood to spawn, or was it conditioning in the form of new food?

I want to see what happens with rainwater alone, no change in diet

[fischfan13]

Ed is being catching a mouse and Melinda ran off and got married this weekend.

Sounds like you might have the most interesting weekend going right now.

[emartin]

Im sure when Ed gets finished putting on Barry Manilow for his laying chickens, he will research the h#ll out of this topic.
:rolleyes:

Right now I am just worried about selling the turkeys and stopping hawks from ripping their heads off. The past two weeks I had hawks kill and eat a turkey, a duck, and a hen.




Oh yeah, and the mouse.


Anyway, I wouldn't use rainwater at all. God knows how much acid and chemicals it washed from the air are in it. Granted that rainwater ends up in all outdoor pond keepers, it's only small amounts (compared to the pond's whole water volume). I would not use large amounts of it for water changes. It would be acidic, among other chemicals and possibly bugs and microorganisms that may be in it.

If you want to induce spawning by mimicing rainwater, build a pvc filter return that drips water all over your tank and drop the temperature by like 5-10F over a couple hours. Then the next day bring it back up (the temperature).

Even then, I am not sure the whole rainwater gets fish to spawn is entirely true. Granted, when the rainy season starts over the rift lakes the fish do spawn usually. But that doesn't mean that if there's a rain storm off-season that all of a sudden everybody starts breeding.

The fish have internal clocks, as well as are dependent on when the flies spawn (midge flies?) and feed on their larva and flies and so on. When everything comes together...the warmer water, abundance of food, etc, they breed.

Personally I think the best methods for getting fish to breed is a high quality diet, and that can be achieved by feeding what is natural to them. A lot of my fish breed after I give them a nice big feeding of frozen glassworms (aquatic midge fly larvae), spirulina brine shrimp (replaces other small crustaceans that could be found in the lake), and freshwater mysis shrimp.

If the fish are REALLY stubborn, I drop the tank temperature down to 70-74F (70F for the deeper water species), and then over a week raise it back up to 82-84F alone with another frozen food feeding and they usually spawn within the next week or two (or at least the male puts pressure on the females and looks amazing).


Anyway the point I am trying to make, I don't think the rainwater thing is worth it. I think it poses unnecessary health risks to the fish (if you use HUGE quantities of it), and imo the fish's diet and habitat are more important to get them to spawn, as well as the temperature.

The easiest and best way to trick the fish it is breeding season is to keep it in a lower tank temperature for a week or so, then raise it back up to what the summer temperatures are.

Acording to Wikipedia, Lake Malawi in the shallow areas/near the surface is 75F in the cooler seasons and 84F in the warmer seasons, and the deeper sections are 72F year round. My WC Nyassachromis boadzulu for example I had trouble breeding back in 2008. After 6 months of waiting, I lowered the temperature from 79F to 71F over a couple of hours which is real close to what the deep water temperature is at the depths they're found out (they're open-water utaka. I don't think they had to be decompressed when caught but they certainly are no where near the surface or shallow areas like some mbuna, lethrinops, and aulonocara are). After fasting them, I fed them frozen glassworms and frozen brine shrimp (most glassworms) and did a couple water changes to raise the temperature back up 79F. Later that week I got two huge spawns, 14fry in one clutch and more than 20 in another (which is a lot for that species).

Just find out what your particular species of fish's habitat is, their diet and temperature fluctuations year round and replicate it. All Lake Malawi fish need is alkaline water. (and calcium seems to help improve their "mood" and colors. I supplement all my tanks with small amounts of pulverized limestone).

A lot of the fish in Lake Malawi, particularly Haplochromines are known to spawn year round so I am certain that rain doesn't have much to do with it. The rain may get their food levels increased, but I don't think it directly affects spawning. (in the sense of the fish are like "Oh it's raining! Time to spawn!" type thing).

For Mbuna and other algae and plant eating fish, the rain likely washes nutrients into the lake which accelerate algae and plant growth. That provides food for the fish through algae and plants, through phytoplankton, for the invertebrates which the fish eat, etc. The invertebrates eat the phytoplankton and algae, fish eat then eat the invertebrates (or the plankton itself which Utaka species do (zooplankton and I think phytoplankton as well), etc...

The only thing I see mimic'ing rainfall that may help trigger spawning is only in Wildcaught species that are extremely stubborn. I still believe though that if you just give them the best diet possible (while I do feed a lot of pellets and flakes, if you breed fish that should NOT be the staple diet, just part of the diet. I only use flakes and pellets for show tanks and growout tanks and quarantine, the breeding tanks get probably 50/50 prepared and frozen/live food...maybe 33/66.

Anyway that's just my opinion. If you do go ahead and try the rainwater as a major water source for the tanks, at least add fresh carbon to remove any potential contaminants from the water to be extra safe. Like I said, even though rain falls into hobbyist ponds, the plants eat up those chemicals and it's still a VERY small amount of rainwater that actually gets into the pond compared to the pond's actual water volume.

[exasperatus2002]

I never used rainwater, but I did have a trio of discus that would only spawn after it rained.

[BlondeFishGal]

Just some observations....

.... a number of people in my fish club collect rain water to inspire fish to breed. Some run it through carbon, some do not.

....outdoor "fish tubs" and water gardens get rain water all summer long. As anyone who has kept fish outdoors in these tubs knows, they breed well in them! In fact, the folks in my club who are into breeding big time pretty much all put fish out in tubs to breed. Actually, my very first year I had one of these tubs, I had neon tetras breed. Not an easy fish to breed, and I never had them breed indoors. I think rainwater does contribute to fish breeding. Now, whether it is the actual rain water itself, or the barometric pressure before hand, I can't say.

....no matter how much my lawn gets watered by the automatic sprinkler system, it never looks the same as after it rains. The rain water is much softer and the growth rate and color of the grass is deeper and more lush after a day or two of rain than if the lawn gets watered for a day or two.

...the 'rainy season' and 'dry season' is well documented in the Amazon. I don't know about in the Rift Lakes, so this comment pertains to the Amazon. But in the Amazon, the fish get various triggers in nature...the rains start, the water rises, bugs/food supply become more plentiful, the daylight hours stretch, and it all triggers the fish to breed. It's Mother Nature at her finest, with everything working in tandem. At the ACA convention, Oliver Lucanas did a fabulous, fabulous presentation about all his collecting experience with fish in the Amazon, and discussed the rainy/dry season and the affect it had on the fish.

[Flareside]

as an update, the rain water experiment was somewhat inconclusive.
I had hoped to get 1st time spawns on some sub adult foai and some adult wc nasuta's. Hours after adding the rain water, both groups were digging in the sand. I learned that I had three male foai- as they colored up quite a bit while they were building two large nests. (now I see the egg spots on their fins much more as well) The male nasuta seemed to be a bit lazy as he didnt build his own nest, he simply dug with the foai on their "community nest".
They do show some breeding activity, but no spawns :sad-smiley-002:

Now, some other fish in the tank were more successful. I have a female calvus guarding a shell. I tried to pick up the shell with my hand and the male and female both will actually bite my hand. Im pretty sure there is something in there. Also I have a group of cyps that are pushed up in the corner. When they swim by the shell, the male calvus chases them back to the corner. If there are eggs or fry in the shell, this will be the first time they have spawned :runnningaround:

Four female cyps are holding for the first time, so Im pretty psyched:becky:

As a bonus, I went to rearrange a rock pile and found that there was a cloud of tiny maleri in there- so the maleri spawned for the first time as well. :coool!:Im certain that most have already become food for the calvus

Did the rain water help to induce first time spawning? I dont know for sure, but with the partial success, I will probably try it again as it didnt seem to have any negative impacts

[BlondeFishGal]

My gut says yes, the rain water helped. I know, I know, not a scientific answer :lol: but it's based on my working with fish in outdoor tubs in the summer and seeing things breed outdoors.

Couple of quick ? for you Les:

Did you do any chemical / pH analysis on the rain water vs. your tap water?
Did you run the rain water through carbon?
Did you heat the rain water (or was it warm enough that you did not need to?)

[Flareside]

Couple of quick ? for you Les:

Did you do any chemical / pH analysis on the rain water vs. your tap water?
Did you run the rain water through carbon?
Did you heat the rain water (or was it warm enough that you did not need to?)

The 125's tank water started at 8.2 for a ph. I added rain water that was between 7.4 and 7.6.

The rain water was 72 degrees. I did not heat it at all nor did I run the water through carbon. I only changed about 20 gals.