Determining the gender of black mollys

[the_elvish_misfit]

I've been sitting and stairing at my two black mollys for some time, trying to figure out what gender they are. (never knew you could tell) Read up on the whole fan fin vs spike tube fin thing and looked at several pictures. But both of my fish (while swimming) look like they have a spike, (while stationary) look like they have fan'd fins. Anybody know a foolproof way to tell?

On one of them those fins are white. I never saw that before, does it make a difference?

 

[missileman]

The males anal fin will look like a spike all of the time.(Gonopodium)
If it fans out when stationary it is a female.

 

[joy13]

If you post a few pictures someone will be able to tell.

 

[missileman]

Here is a fair pic.
The one in the front is female, the one in back is male.

 

[the_elvish_misfit]

Aha thanks guys. Now that I have one of each it's much more clear.

 

[Nyquil Junkie]

if you have a pair, separate them or you will be ankle deep in the little buggers

 

[the_elvish_misfit]

if you have a pair, separate them or you will be ankle deep in the little buggers

That's ok, I have a breeder box and several other tanks. Plus my male is deformed or paralyzed so I doubt he can get in the position to breed anyway.

 

[krap101]

If it is genetic, he could be spreading it, if he *can* get into the position..

 

[the_elvish_misfit]

If it is genetic, he could be spreading it, if he *can* get into the position..

He has to constantly keep his whole body wiggling, and even if he does, it's not like they're show fish and I may just let the fry do their thing in the tank. Nature and all that. If not we'll see what happens.. could sell em back to the pet store.