This is why learning scientific names is important...

[Snagrio]

I've been delving more intricately into just what specific hatchet fish I have, and they are not Gasteropelecus sternicla as I initially thought. Apparently there are what seems to be 4-5 different species that all share the name of "common" and "silver" and image searching only makes things more confusing by mixing them up further.

Instead, I believe they are Thoracocharax Stellatus, commonly called "silver" (which is what they were sold as) or the more appropriate "spotfin" hatchet. I figured this out because recently, they've started to develop black coloration on their dorsal fins, something I've never seen in most images of hatchets in general, but turns out to be a signature of T. Stellatus.

Couldn't get good pics of my own because of lighting/movement/bad phone camera, but this is what they look like now.

Notably, some have started to show courtship behavior (swimming side by side in a kind of duet), and when they do almost their entire dorsal fin flushes black.

 

[OnlyGenusCaps]

Yes! Agreed! Scientific names are important!

 

[Sgooosh]

Yes! Agreed! Scientific names are important!

it is also important because of breeding compatibility i think. like poecilia can breed with other ones like guppies x mollies

 

[OnlyGenusCaps]

First off, monkeys... Yes!

Breeding is an issue in terms of how species are classified. Horses (Equus ferus) and donkeys (Equus africanus): no bueno. But guppies (Poecilia reticulata) and Endler's (Poecilia wingei): get. it. on. Some species can interbreed easily, and others have sterile or no offspring. Some orchids can even make intergeneric hybrids. Sadly, for hybridization, species classification is no guide.

Although, I suppose in the case you raise, it does give you a guide. And, I completely agree that it helps in determining what you have an how to care for it. Plus, and this might not be a secret at this point, I'm a science nerd.

 

[Sgooosh]

First off, monkeys... Yes!

Breeding is an issue in terms of how species are classified. Horses (Equus ferus) and donkeys (Equus africanus): no bueno. But guppies (Poecilia reticulata) and Endler's (Poecilia wingei): get. it. on. Some species can interbreed easily, and others have sterile or no offspring. Some orchids can even make intergeneric hybrids. Sadly, for hybridization, species classification is no guide.

Although, I suppose in the case you raise, it does give you a guide. And, I completely agree that it helps in determining what you have an how to care for it. Plus, and this might not be a secret at this point, I'm a science nerd.

thanks, im not that much of a nerd myself for livebearers it helps, as the poecilia and the xiphoporus(?) cant remember
can all breed together..

 

[Essjay]

Some Poelilia species can breed together eg endlers and guppies. Some Xiphophorus species can breed together eg platies and swordtails. But Poecilia can't breed with Xiphophorus.

 

[Sgooosh]

Some Poelilia species can breed together eg endlers and guppies. Some Xiphophorus species can breed together eg platies and swordtails. But Poecilia can't breed with Xiphophorus.

hmm, examples? are they all liovebeareres?

 

[Byron]

As those who remember me will know, this is my first post in several months; the saga of my on-going cancer battle I will leave for another time, but now offer some guidance on your question. Hatchetfish are a particular interest to me, I have kept most of the species over the years and studied them extensively. Much of the data in the SF profiles of the Gasteropelecidae species is my work.

Common names are useless for just the reason you mention, and I have seen three different Carnegiella species (four if you count the fool who had Marble Hatchets so labeled and argued with me about them) as well as one Gasteropelecus and one Thoracocharax species all labeled "silver hatchet" in stores.

The family Gasteropelecidae contains three genera. Thoracocharax, the most primitive and distinguished by its impressive keel, contains two species, T. securis and T. stellatus. Gasteropelecus contains three recognized species, G. sternicla, G. maculatus, and G. levis. These two genera contain the largest in size of the hatchetfish, and all are silver in colouration; G. sternicla is the more frequently seen of these five species, though any of them are frequently offered as "Silver Hatchetfish." The third genus, Carnegiella, contains four species that are the most derived or specialized of the hatchetfishes, and all are smaller and lack an adipose fin. They are easiest to identify, though the recent evidence of a species complex of sorts among the C. marthae/C. schereri species and the two clear forms of the "Marble" species does complicate matters, but externally these species are all quite distinctive; the absence of an adipose fin in the Carnegiella species (it is always present in the other two genera) is the easy method to ID them.

The pictured fish (post 1) is likely Thorocharax stellatus. It is not G. sternicula because of the lack of a clearly defined lateral stripe and the presence of the black blotch in the dorsal fin. I had a group of this species for several years, and in a dim-lit tank they are indeed true beauties. And their playful interactive behaviours were non-stop, unlike anything I have seen in the other species; your observations bear this out. Lovely fish if one can find them.

 

[EllRog]

As those who remember me will know, this is my first post in several months; the saga of my on-going cancer battle I will leave for another time, but now offer some guidance on your question. Hatchetfish are a particular interest to me, I have kept most of the species over the years and studied them extensively. Much of the data in the SF profiles of the Gasteropelecidae species is my work.

Common names are useless for just the reason you mention, and I have seen three different Carnegiella species (four if you count the fool who had Marble Hatchets so labeled and argued with me about them) as well as one Gasteropelecus and one Thoracocharax species all labeled "silver hatchet" in stores.

The family Gasteropelecidae contains three genera. Thoracocharax, the most primitive and distinguished by its impressive keel, contains two species, T. securis and T. stellatus. Gasteropelecus contains three recognized species, G. sternicla, G. maculatus, and G. levis. These two genera contain the largest in size of the hatchetfish, and all are silver in colouration; G. sternicla is the more frequently seen of these five species, though any of them are frequently offered as "Silver Hatchetfish." The third genus, Carnegiella, contains four species that are the most derived or specialized of the hatchetfishes, and all are smaller and lack an adipose fin. They are easiest to identify, though the recent evidence of a species complex of sorts among the C. marthae/C. schereri species and the two clear forms of the "Marble" species does complicate matters, but externally these species are all quite distinctive; the absence of an adipose fin in the Carnegiella species (it is always present in the other two genera) is the easy method to ID them.

The pictured fish (post 1) is likely Thorocharax stellatus. It is not G. sternicula because of the lack of a clearly defined lateral stripe and the presence of the black blotch in the dorsal fin. I had a group of this species for several years, and in a dim-lit tank they are indeed true beauties. And their playful interactive behaviours were non-stop, unlike anything I have seen in the other species; your observations bear this out. Lovely fish if one can find them.

You've been missed, sir. Welcome back