I've got a question about rain and cory spawning...
I've read repeatedly about corys spawning after rains because of "cooler water". I was wondering if there is official evidence of that?, such as have people actually compared spawning rates with doing water changes with cooler water versus water the same temperature?
The reason I ask is because so many posts are saying the cooler water tricks the cats into thinking it's the rainy season and the "cool" rain water runoff triggers the fish to spawn. I'm wondering if this has been proven, or is just theory from people who associate rain with cooler water? From my 14 years of living in the tropics, the warmer it gets, the more it rains, and the rain comes down warm, unlike in temperate zones. There may be some evaporative cooling going on as it falls, but it's coming down warmer than temperatures can be in cooler seasons, and once it hits ground it's certainly hitting warmer ground than in cooler seasons.
Years ago I had a friend that was pretty successful with breeding cory cats and he said he would just ignore their tanks for a while, then start pumping up the water changes when he felt he wanted to deal with fry... he never mentioned cooler water, but I don't know for sure what he was doing in those regards.
Could it be that fresh, well oxygenated water is cleansing the waters they live in and that triggers spawning? I'm just wondering if the cool water theory is perpetuated conjecture or if people have really compared water changes with cooler water versus with water of the same temperature. A quick google search has gotten me nowhere with it.