Sexing Questions

[randymyr]

I know some fish it's harder to tell how to tell the sexes apart, but I was wondering if anyone here could help me with sexing some of my fish.
I wasn't really planning on breeding fish, but it'd just be helpful knowing if there is a possibility of getting some babies in the future.
1. I was wondering how to sex giant danios, I've been reading around, and have barely came up with any information at all, all I've found is there is more of a "belly" on females, and they are less colourful than the males. And since i'm on the topic of danios right now, two of mine have these strange red fins, and they also seem to be swimming around more than the other two, what could this be?
2. Now, I'm wondering about penguin tetras, I haven't found any information on them at all!

 

[Ripley]

Danios and most tetras are a bit difficult to sex, as I am sure have noticed by your research. I have bred Gaint Danios in the past, and all I have noticed between sexes was the difference in size. If you are planning on breeding them, it is best to take them out of the community tank and into a breeding tank. Once the Danios start to breed you can tell the differnce of sexes easily, as the male is the one doing all the dancing. You best bet is to place 4 adults in the breeding tank, you should get a pair out of them. As for the redish fins, I would'nt worry about. In the past I found that some of breeders would get some red on their fins and they are still swimming.

 

[randymyr]

Danios and most tetras are a bit difficult to sex, as I am sure have noticed by your research. I have bred Gaint Danios in the past, and all I have noticed between sexes was the difference in size. If you are planning on breeding them, it is best to take them out of the community tank and into a breeding tank. Once the Danios start to breed you can tell the differnce of sexes easily, as the male is the one doing all the dancing. You best bet is to place 4 adults in the breeding tank, you should get a pair out of them. As for the redish fins, I would'nt worry about. In the past I found that some of breeders would get some red on their fins and they are still swimming.

so is there any way to tell if the danio is getting ready to lay her eggs? or does it happen randomly in the breeding tank?