Need advice on stimulating the transition from dry season

[tigger27]

I have a trio of L46s that i want to breed this year. I have read up on some of the articles that advise stimulating the dry season first and then transition into the rainy reason to trigger their breeding. I know that some people have already gone through this or is in the process and i'm doing this kind of late because i just moved them into a new tank about 3 weeks ago so it was not possible to start sooner. Here is a little background of my setup. It consist of a 20 gallon long, bare-bottom tank with two air driven sponge filter and a third that is powered by a maxijet 600 powerhead. I keep an extra sponge filter in each tank because i'm expecting some new arrivals soon that i will setup another 20L for. There are 3 caves and three other hiding places made up of slates and rock formations for the trio. The male has already chosen his cave and the two females also have shown interest in breeding. They constantly swim by his cave, but he comes out and nudges them away. They are around 4 to 5 years old and the females are gravid, so it seems like they are ready but he isn't. From some of the articles i read, it seems like i have to start with an extended time of no water changes for around 3 weeks and then start 50% water changes on the fourth week once every other day for one week with 25 degrees C water. During this no w/c period about 1 inch of the water evaporates over the course of 3 days, so i think i will have to replenish it. Another variable in the transition is the current. It is my understanding that in the dry season the current is slower so I was planning on shutting off the powerhead during the first 3 weeks and only turning it on when i start the water changes. The frequent w/c are suppose to occur every other week to stimulate the rains. How long do I have to keep this up for? Is it up until the point where they start breeding? Or should i continue this for 2 to 3 months to stimulate the rains? Any advice would be greatly appreciated.

[Shane]

There are other forum members far more qualified than I to discuss spawning H. zebra. I am not aware of any information that they are seasonal spawners, nearly all Hypancistrus are not. Seasonal spawning is much more associated with loricariid spp from environments that under go radical wet/dry season changes like spp from the llanos and piedmont streams. Most large river dwellers, like H. zebra, are simply not bound to small seasonal windows where they must spawn before they die off in large numbers during the dry season.

Anyway, the general parameters of the South American dry season (and things that can therefore be reproduced in the aquaria as a simulation) are:
1) Higher water temps
2) Less current
3) More light (no rain clouds to block the sun out)
4) Less food
5) Higher TDS (due to evaporation)
6) Lower O2 levels

Dry season simulations can be as short as a couple of weeks for many spp or even shorter. Many loricariids and Corydoras can be "tricked" with nothing more than a large water change with slightly cooler water as this lowers temp and TDS while raising O2. More difficult fishes may require 7-10 days without a water change followed by a 50% change with RO or rain that is a few degrees cooler and the addition of an air stone. Really difficult spp may require several days of 30-40% water changes with cooler, softer water, the presence of large amounts of food, the addition of a powerhead, and the tank lights left off for several days.
-Shane

[exasperatus2002]

I dont know if it'll help but when I tried breeding red eyed tree frogs, I'd hook up a spray bar & let it rain for a few hours a few times a day to simulate the rainy season. Drove the males nuts but the females wouldnt cooperate. Dont know if the artificial rain will help with fish though as long as theres a fresh influx of water.