New Hatchet fish Chasing Each Other

[MuddyWaters]

I bought some Silver Hatchet fish. They came in groups of 5. I kind of wanted 6, but didn't want 10, so I got 5. They're in my 75 gallon tank, lots of swimming room and have floating plants up top because I read that would make them happier (red root floaters and big pile of water sprite).

Mostly they're doing great- they have settled in and the coloring has come in beautifully- nice stripe along the back and some dots, etc.

However, one or two of them tend to chase the others. I don't see them actually snipping, and they don't bother the tetras, even when they're swimming together, but they do chase each other some.

They're eating well, water parameters are great, etc.

Is this just new tank adjustment or is there something else I need to check? I know tetras will chase each other around sometimes more like playing, and I'm tempted to believe that's what is happening with the hatchet fish too, but it's so explosive when one chases the other, it's kind of unnerving. They are super-fast and very agile. It's cool to see, as long as I'm not watching them killing each other LOL.

Anyone else had Silver Hatchetfish that chase each other around?

 

[GaryE]

It's what they have always done here. They always chase.

 

[MuddyWaters]

It's what they have always done here. They always chase.

ok good- it's a relief to read that, GaryE. thanks. I love watching them- they're very active.

 

[Byron]

Agree, this is a natural behaviour of almost all characins. "Silver Hatchetfish" can apply to several basically silver species, and I have had all of them, which one do you have? Their are differences.

 

[MuddyWaters]

Agree, this is a natural behaviour of almost all characins. "Silver Hatchetfish" can apply to several basically silver species, and I have had all of them, which one do you have? Their are differences.

Byron, not sure- I got them at Aqua Huna (here's the page). They have a nice little stripe along the back and a black stripe at the bottom of the dorsal fin. Also some "freckles" along their sides toward the top of the back. I was nervous to get them because of the jumping, but I read that Silver Hatchet fish don't jump as much as others. So far, no jumping, thank goodness.

 

[Byron]

Gasteropelecus sternicla. The photos were rather misleading with the colouration, but they gave this down the page so it is correct.

Hatchetfish have a slender body with a deep "belly" and pectoral fins that are set high on the body and attached to very powerful muscles. These fins propel the fish from the water, enabling it to glide considerable distances through the air. Studies by Francine Weist (1995) concluded that the pectoral fins are not moved during this "flight" but are used as a powerful thruster to propel the fish from the water as well as to prevent the fish from diving too deeply upon its return to the water [reported in Weitzman & Palmer, TFH, September 1996].

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.

The tank must be well covered, regardless of plants.

 

[MuddyWaters]

Gasteropelecus sternicla. The photos were rather misleading with the colouration, but they gave this down the page so it is correct.

Hatchetfish have a slender body with a deep "belly" and pectoral fins that are set high on the body and attached to very powerful muscles. These fins propel the fish from the water, enabling it to glide considerable distances through the air. Studies by Francine Weist (1995) concluded that the pectoral fins are not moved during this "flight" but are used as a powerful thruster to propel the fish from the water as well as to prevent the fish from diving too deeply upon its return to the water [reported in Weitzman & Palmer, TFH, September 1996].

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.

The tank must be well covered, regardless of plants.

Thanks, Byron! Yeah I have a decent amount of floating water sprite- it'll grow, presumably, as will the red root floaters. They also have a darker spot at the top in the back and they hang out there where the spray bar is. They seem to be pretty well adjusted, and interestingly, they don't really go into the water sprite. They do hang out where the red root floaters are. That's where I feed them too, so that might be why.