Sexing Chaetostoma formosae

[Casscats]

I picked up a group, hoping for a pair.


There are 4 fish, including my original fish.

I am thinking there are 3 females and 1 male?

[bekateen]

I think at least 1M:1F. But easier to sex from looking at upper lip, I think.

Cheers, Eric

[Casscats]

I think at least 1M:1F. But easier to sex from looking at upper lip, I think.

Cheers, Eric

There are 4 fish in question.

The page for the species on these claim they can be sexed using the pelvic fins, stating males have extended points?

[Casscats]

What exactly do you look for on the upperlip? I can net each individual tomorrow for lip photos, they're in my quarantine tub for now and I don't want to disturb them so soon after acclimating them.

[Casscats]

Oh wait I do have these photos of above on the new ones.

But if better is needed, I will take better photos tomorrow.

[bekateen]

The page for the species on these claim they can be sexed using the pelvic fins, stating males have extended points?

Yes this is true. If you're fish are mature, I see only one fish with extended pelvic fins, although the difference is not dramatic in your fish (maybe not fully mature, or maybe need conditioned?).

What exactly do you look for on the upperlip? I can net each individual tomorrow for lip photos, they're in my quarantine tub for now and I don't want to disturb them so soon after acclimating them.

Males develop a bigger upper lip extension than females, if in not mistaken. Certainly true for some rubberlip species, but maybe not all.

I hope you succeed in breeding them. Rubberlips are hands- down my favorite plecos, but I've had nothing but bad luck with them.

Cheers, Eric

[Casscats]

The page for the species on these claim they can be sexed using the pelvic fins, stating males have extended points?

Yes this is true. If you're fish are mature, I see only one fish with extended pelvic fins, although the difference is not dramatic in your fish (maybe not fully mature, or maybe need conditioned?).

What exactly do you look for on the upperlip? I can net each individual tomorrow for lip photos, they're in my quarantine tub for now and I don't want to disturb them so soon after acclimating them.

Males develop a bigger upper lip extension than females, if in not mistaken. Certainly true for some rubberlip species, but maybe not all.

I hope you succeed in breeding them. Rubberlips are hands- down my favorite plecos, but I've had nothing but bad luck with them.

Cheers, Eric

My original fish is a mature 4-5 inch fish, the one that says original fish in the pic (if we can sex that one especially, would be fantastic)

The 3 new are only 3 inches, so suspecting still coming into sexable sizes.

I adore the first one we got, they're really outgoing and active. A bit bossy which is amusing as it fearlessly fends off my h. punctatum if they sit on the same rock lol. I'm working on building a "colder" temperature tank with the c. formosae and c. paleatus.

Was hoping for a pair and someone had a couple for sale so figured I'd opt for the group and see if there could be a pair among them. I have a friend who would be interested in the extra male if there is more than 1 male.


This is the original fish, some pics defending the rocks lol

[Shane]

Note swollen lip of sexually active male.
-Shane

[Casscats]

Note swollen lip of sexually active male.
-Shane

The pale rim to the lip, yes?

Around what size would this be most apparent?

[Shane]

It is not related to size. Any sexually mature male will develop the lip and extended pelvic fins if they are healthy and females are present.
-Shane

[Casscats]

It is not related to size. Any sexually mature male will develop the lip and extended pelvic fins if they are healthy and females are present.
-Shane

Going by that, would you say the original fish is male or female? Lacks the fin extensions but lip looks more swollen than the younger batch.

I am not planning to keep more than 1 male, I'd like to keep 1 male with a group of females Ideally. The seller had no clue what were what so I figured it'd be better to buy the group he had and figure it out myself lol my original fish is staying with me, but I've got a friend interested in taking one extra fish after they're out of quarantine

[Casscats]

@bekateen @shane

Took them out for photos of their upper lips. I will do each individual as it's own reply for easier organization. If you can label who's what would be great.

However, I'd like to confirm for sure if original fish is male or female (think it was said probably male before)

This is original fish above lip shot when I got him

[Casscats]

Fish 1. I am going to guess female?

[Casscats]

Fish 2 I am fairly certain is male, this one shows fin extensions

[Casscats]

And fish 3, I want to guess female.

[Shane]

My best guess is two males and two females. Put them in a proper set up and you will quickly see the males develop obvious sexually dimorphic characteristics.
-Shane

[Casscats]

Fantastic, thank you, so assuming my guesses are probably correct. Giving it a few weeks before they're put together. I had to cull a tank due to medication resistant disease, so I'm super paranoid of that all over again, so they're in a quarantine tote. The 3 new ones are together, but not my original.

I'll be doing the original with the 2 females and a friend is probably taking the extra male.


Edit: took a close look at my original, and he has definitely developed the extentions to the pelvic fins since that photo of him last on the glass, so I have no doubts whatsoever on him being male.

I think that works out perfect, once QT is done he can move in with the two ladies and the extra boy will have a home with a friend without having to fight or be bullied (my original one is a bit of a brute)

Thank you for the help