Dry season simulation?

[Hybridfish7]

So we all know how to replicate rainy seasons, whether it be the simple "do cold waterchanges and add flow to the tank", or the more complicated "fill the tank with ice cubes and let them melt"/"drill holes in a pvc pipe to pump rainwater in and simulate rain". However, going backwards a bit, how would one go about simulating a dry season? After looking around CRC, I've found most of the cichlids that I am currently trying to breed/want to breed/have trouble breeding spawn in the spring/dry seasons of their native ranges. How would one go about simulating this? I have a feeling duanes may be able to chime in on this.

 

[Niki_up]

Don’t take my word for this as this is just my own “theory” that seems to make sense in my mind. It may not make any actual sense.

I would leave the tank lid off, lower the filter intake tube close to the bottom of the tank, allow the water to evaporate from the tank and only do top ups. This should make the water level low signalling to the fish it’s dry season, it should also compound all the water parameters you would think will be higher in the dry season bc of the lack of incoming fresh water. Maybe try turning the water temperature up to signal to the fish it’s hot outside and the water is evaporating.

I’m not sure how long you could safely do this in a tank as we know the nitrates will also be building in the tank which isn’t good for the fish. I would think two weeks is doable in a reasonably stocked tank without causing too much harm. Though to be fair it’s probably not ideal.

I will admit I neglected one of my tanks for two weeks and allowed this to happen and when I did my water change it caused spawning immediately. I may even re-try it as I really want this species to produce fry for me

 

[Hybridfish7]

Don’t take my word for this as this is just my own “theory” that seems to make sense in my mind. It may not make any actual sense.

I would leave the tank lid off, lower the filter intake tube close to the bottom of the tank, allow the water to evaporate from the tank and only do top ups. This should make the water level low signalling to the fish it’s dry season, it should also compound all the water parameters you would think will be higher in the dry season bc of the lack of incoming fresh water. Maybe try turning the water temperature up to signal to the fish it’s hot outside and the water is evaporating.

I’m not sure how long you could safely do this in a tank as we know the nitrates will also be building in the tank which isn’t good for the fish. I would think two weeks is doable in a reasonably stocked tank without causing too much harm. Though to be fair it’s probably not ideal.

I will admit I neglected one of my tanks for two weeks and allowed this to happen and when I did my water change it caused spawning immediately. I may even re-try it as I really want this species to produce fry for me

This is the more straightforward answer I was thinking of, I've even tried this with cardinal tetras (didn't work). Hopefully there's a safer and more reasonable way to do this.

 

[duanes]

It is the dry season here in Panama at the moment.
And because my tanks are outside, some "pseudo" natural things occur during this time. (even in a recirculating system)
As the rainy season ended, (when it did rain) tannins from the surrounding drying vegetation inundated the tank, and more leaves, fallen flowers and branch litter fell into tank and tinted the waters color.

As an experiment to keep a higher tannin concentration, instead of 3 or 4 regular 30-40% water changes per week, I have cut back to two, which has allowed for more evaporation, and a lower water level in the sump, and the tannins not to be washed out.
The normal water change routine (and every day rain inundations) during the rainy season, normally maintain the sump almost full.

Since rains have stopped, and I cut back a little on filling after the smaller water change routine, evaporation has lowered the sump surface, by at least 6 inches, and the mangrove roots, and bamboo tubes they are planted in, (normally submerged) are now breaking the surface.


Even with a couple less water changes per week, nitrate is so far, undectable, and pH has not fallen (still 8.2), "probably" because of the intensely planted sump.
Although that's not that surprising, because stocking levels are low.
It is breeding season for the Andinoacara, and as usual, they have taken advantage of the fallen leaves to spawn on.

My theory is....with such a heavily planted sump, the plants remove nitrate almost as fast as the fish can produce them.
Beside the Vallisneria, Hygrophilla, and water lilies, I have recently added floating Salvinia and water lettuce, and there are at least 10 young mangrove sapplings in the sump, and some terrestrial plants as well (and some in the main tank).

 

[duanes]

At this time of year, most small natural pools, are inundated with leaf liter., and brown with tannins.
The one below, had about a 6" matt of leaf litter covering the bottom. (shots taken in Jan a few years back)

 

[duanes]

Sump water level is really down this morning.

 

[Niki_up]

This is the more straightforward answer I was thinking of, I've even tried this with cardinal tetras (didn't work). Hopefully there's a safer and more reasonable way to do this.

I have seen a few people breed cardinal here locally and I do not believe they simulated a dry season.

cardinals lay eggs in the wee early mornings with the first glimmer of sunshine. So if you do not have a breeding mop to catch the eggs any eggs that get laid are undoubtedly getting eaten before your feet even hit the floor in the morning.

I’d you have not tied that then that would be your best first step. Having them alone in a tank, no other tank mates will help as well.

 

[tlindsey]

cardinals lay eggs in the wee early mornings with the first glimmer of sunshine. S

I've had Congo Tetra do the exact same thing a few times.

 

[Hybridfish7]

I have seen a few people breed cardinal here locally and I do not believe they simulated a dry season.

cardinals lay eggs in the wee early mornings with the first glimmer of sunshine. So if you do not have a breeding mop to catch the eggs any eggs that get laid are undoubtedly getting eaten before your feet even hit the floor in the morning.

I’d you have not tied that then that would be your best first step. Having them alone in a tank, no other tank mates will help as well.

The no spawning mop bit was probably my downfall there but I did have a layer of mulm and leaves that I thought would do the job to a degree. They were in a sun lit 10 gallon with no light or tank mates, never ended up seeing any fry.

 

[Niki_up]

spawning mop is probably a must, once they complete laying you would need to remove the mop. The parents and other fish won’t hesitate to eat the high protein egg snack. Some people even go further and remove a single male and female into a breeding tank with a mop.
Floating plants like duckweed also help hide the tiny tiny fry