Just girls?

[Henry5]

Just out of curiosity; can a batch of guppy concists of only females? Or only males? Or are they always mixed?

[Komar]

Generally, try to keep about twice as many females as males. Males tend to bicker if there aren't enough females. (All females wil probably be fine, though probably not all males.) Males are also usually far more colourful, so it's sometimes hard to resists putting more of them in together.

[ladyjai]

all males are fine, provided you don't take offense to them attempting to mate with each other. I'd keep a group of 3 minimal, if you are worried. aggressive guppies are extemely rare, though.

if you have females mixed in, you must follow komar's rule 1M:2+F. otherwise all the males will gang up on the poor gals.

[Komar]

I've never kept all males, though when the male:female ratio was 50:50, the bigger males seemed to get aggressive (to both the males and the females). I guess it's not unlike going to a crowded dance bar and seeing a bunch of drunk young fellows looking for a fight. Heh.

(I'm starting to think I've had lots of exceptional fish: a guppy-eating pleco, aggressive guppies, and an aggressive Pearl Gourami. Maybe I should lose the fish and get birds instead... )

My only experience is with feeder guppies, though. I used them to "break in" an aquarium awhile back, and have kept a few on hand since then, after noting some nice colouration in a few of them. Even the feeder guppy males eventually get some nice colours, but fancy guppies really are just that; fancy.

[ladyjai]

between me and my father, i've had several thousand fancy guppies come my way. so that is my experience. he and I have kept male only tanks also. I've mixed males into community tanks, and he's stuffed 20gallons with 20-30 males.

of course, when you have a 50:50 ratio, you may have problems in the males being so frantic for the females they just go nuts. but did you witness actual biting, or gonopodium pestering? or damaged fins? I'm just curious.

male feeders can be very nice looking.

aggressive pearl gouramis. i've never kept them, but it has been my understanding that gouramis in general are wicked to each other and angels (unless you manage a pair). of course, diffences occur in each species grouping, but.. dunno..

[Komar]

"Gonopodium" -??? Let me do a quick Google definition search...

"A specialised anal fin used for internally fertilisation a female livebearer."

(Wow, awesome grammar...)

I saw what looked like nipping and bullying, but I don't recall any fin damage, so if there was any, it wasn't too frequent. I think the males were just going nuts, as you say, so I split them up.

(I kept some guppies just because I liked their colouration too much to feed them to my other fish. )

I've always heard that Pearl Gouramis are docile in a community tank or in a group. My understanding was that they only got aggressive when it was time to breed, if the male:female ratio was unfavourable (as with guppies). I think your sources are more accurate...

[Henry5]

No, I ment when they are born. Can a guppy give birth to only females? Or only males? Or are they always mixed?

[NorthernFishHead]

Henry5: Im sure this is an old topic. But. Your fry will consist of both females and males. You won't be able to tell their gender until they are between 1 to 3 monthes of age. They may all look like females but you will be suprized when some of them pop up beging males in the end. :).

[nick_cave]

Guppys as all species have primary and secondary sexual characteristics:

by defenition primary are all that born with the fish, and secondary all that apear after a period of development. (in guppys as well put by NorthernFishHead, this period can be between 1 to 3, but up to 5 months to full development)

Primary sexual characteristics are internal organs, all fish born with they gender defenition given by contribution to their genes by both parents (there are some exceptions)

Secondary sexual characteristics are (in Guppys), presence of gonopodium ("A specialised anal fin used for internally fertilisation a female livebearer.", good defenition go Google!), in males, bigger fuller bodys in females, as oposed to shorter thinner bodys in males, more colorful males (although several strains of females are also very colorfull), but also some behavihour characteristics, males show most intrest in other of their species, and also flare their fins to females, trying to atract them.
All these contribut to sexual dimorfism, what allow us to tell males from females guppys
When they are born they all resemble females, but then their charatecristics diverge acording to sex. Yet is not statistical improbable that all fish in a batch are females of course.