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I've a group of Otocinclus flexilis I've been trying to breed, on and off, for the last two years, without any success. Standard seasonal simulation has led to some behaviours I interprete as prelude to spawning, but never any actual spawns.

I've started suspecting that maybe they need to overwinter to breed?

Now, I have a frost-free balcony, and I could put an aquarium there over the winter - but the temperature there is just above freezing, typically about 5 celsius (41F).

* Would they be likely to survive that low a temperature?
* Feeding. Goldfish can't be fed while hibernating, how should I treat the flexilis?
* Anything else I should consider?

Weather in Santa Maria, Brazil. So the average LOW of the 24hr period (early morning) would be around 8-9 degrees.

The water temperature in the river would be higher than this, tho'.

If you plan on doing this, I would put them outside around this time of the year, and then take them back inside before it drops below 10'C in the water [you'd probably need a min/max water temp meter to judge that, but checking early in the morning would be a second option for that - give yourself a little extra margin if you do that tho'].

Only small amounts of food during the "winter", as with all cold-blooded animals, the metabolic rate is relative to their temperature...

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Mats

Inspired by that link I started searching for min/max records for Buenos Aires (as O. flexilis is found there), and in the coldest month the mean low is 5C, and mean high 15C.

I'd say that your advice to aim for a low of 10C in the water is a very reasonable estimate, and I really must thank you for your suggestion to let them "overwinter" now during the autumn, I can't believe I didn't think about that myself!

As it turns out, I have a 40-liter barrel on the balcony with healthy algal growth, I'll move the otos there, together with a piece of driftwood & a mini/max thermometer. When the water temperature hovers around 10C I'll move them inside and see if they feel like spawning.

Mike_Noren wrote:I'd say that your advice to aim for a low of 10C in the water is a very reasonable estimate, and I really must thank you for your suggestion to let them "overwinter" now during the autumn, I can't believe I didn't think about that myself!

That's why disccusing with other people works...

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Mats

If this helps to you, here where we find o. flexilis the water during almost all the winter have a temperature that around 5-8ºC depending the place (the temp that you mention about Buenos Aires is for the city, in the fields usually is below 0ºC at early morning) and the fish is found in qtty and in excellent shape during this season of the year. Breed take place in middle spring, water temp about 13-15ºC at least in the places that we research and usually eggs are layed in soft roots (maybe you can try with some kind of mop as for killies?)
Hope that helps

AGV wrote:If this helps to you, here where we find o. flexilis the water during almost all the winter have a temperature that around 5-8ºC depending the place (the temp that you mention about Buenos Aires is for the city, in the fields usually is below 0ºC at early morning) and the fish is found in qtty and in excellent shape during this season of the year. Breed take place in middle spring, water temp about 13-15ºC at least in the places that we research and usually eggs are layed in soft roots (maybe you can try with some kind of mop as for killies?)
Hope that helps

Oh yes, that is invaluable information!
That is not only support that they may need very low temperature to condition them for breeding, but also suggests what temperature I should aim for to simulate "spring".

As for breeding, I will supply them with lots of javamoss and floating Pistia plants with long roots, which hopefully should be acceptable to them. I am considering also keeping them with Corydoras paleatus, as there is a report that a trigger for flexilis to spawn is the presence of breeding Corydoras.

Thanks!