How often will glowlight tetras spawn

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seangee

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Last night I noticed the females looked ready to explode. Tonight they are even bigger and there is an awful lot of chasing going on in the tank (males chasing females), even though the lights are still on. I'm away from home for 3 days leaving early tomorrow so can't do anything about it now. With 19 corys in the tank, not to mention the 40+ tetras, I suspect nothing has a chance of surviving.

Am I right in thinking that the weekend will be too late to put up a spawning tank? If so how long should I wait to actively try? The last time I noticed this behaviour (and oversized bellies :)) was about a month ago just before I went on holiday. I suspect conditions are considerably better for them now as the tank is a good 5 degrees cooler and this week has been decidedly inclement.
 
The behaviour must be contageous. A few of the cardinals are also chasing each other around. The females don't look nearly big enough and I know these are almost impossible to breed by accident. I already have around 30 of these so I won't be trying to increase their numbers just yet ;)
 
Most tetras will breed every 1-2 weeks when kept under good conditions.

If they have started displaying now, then leave them be. They should have finished spawning by tomorrow.

Fish release hormones into the water when breeding and this can encourage other fish in the tank to breed. I use to put rainbowfish into tanks with Corydoras to encourage the Cories to breed. Rainbows are randy little sods and breed continuously for months. While breeding they release the hormones into the water and the Cories would usually start to breed as well. Once the Cories had bred I move the rainbows back to their own tank and rear up Cories and rainbows together.
 
"Randy little sods" . If you knew how that sounded to the American ear you would be howling gales of laughter like I am now. With your permission Sir, I will add that to my list of go to phrases for special occasions. :rofl:
 
You mentioned the weather. I have always suspected that barometric changes and even the moon affect fish. What do you think ?
I have long thought that the rainy season triggers spawning. Its one of those things I think I "know" but no idea where I know it from. I also know that temperature drops raise the general level of excitement in the tank, so I don't bother much about temperature matching at water changes. Byron has recently posted a few times about barometric changes. This makes sense but I was not aware of it.

All in all right now in this part of the UK we have the makings of a perfect storm:
  1. Summer has now moved over the horizon and the heaters have been coming on regularly for the last 2 weeks - so the average tank temp has dropped by around 5 degrees C
  2. After a hot dry summer the weather this week has been more typical of what people think of as typical British weather - i.e lots of rain every day
  3. Linked to above our little island has been hammered by a series of frontal systems moving across the Atlantic from the West - thank you America :mad:
So, as Colin so eloquently expresses it, my tanks are full of randy little sods :fish:
 
About half of the female tetras are now skinny. The rest aren't - so I will set up a breeding tank tonight.
 
Breeding tank up and running. My study is now a noisy zone with the air pump buzzing away in the corner.

Went across to the tank last night to net some fish and caught most of the little s*ds in fraganti ;). Decided the stress of being netted that late in the process was not a good idea so I'll wait till the next time around - unless I get impatient and go fishing for CPD over the weekend as I would rather like to increase their numbers too.
 
Made an important decision on Saturday, yes they are ready again and Colin is right again. I was about to catch some tetras during the water change to move them into the breeding tub which has been getting ready for the last week when I remembered something that I have known all along...

My interest / hobby is keeping tropical fish - not breeding them. Since I am working full time again remebering this was actually quite a relief. So its back to my non-intervention approach which means I will only rarely see new fry appear (lots of shrimp though) and not have to worry about breeding or raising fry.
 
You should breed them even if it's just for experience. You never know when you are going to need to breed and grow fish for various purposes.
 
Just the fact that you actually see tetra fry on occasion is immensely cool. Few people do.
Never actually seen the tetra fry. I have seen them spawning. I already have 14 glowlights so although I wouldn't mind a few more I don't have the tank space for too many. The only fry that have survived in this tank have been pencilfish (n.marginatus). I started out with 19 and have 24 now.

I have had a few CPD survive in another tank. If I do actively try to breed anything it will be these. I can't find any info on their lifespan but I suspect it may be fairly short. I have had mine for around 18 months. I know they were at least 6 months old when I got them and their numbers have started to decline. I started with 24, have had (at least) 3 born in the tank and only have 19 now. No signs of illness or stress, so I suspect its just natural causes.
 

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