Hoplias curupira - courtship or fighting?

[TheMarburn]

Hello everyone,

i'm new at keeping bigger fish but got the chance to buy two (supposedly) hoplias curupira. One of them is a little more "bulky", while the other one's rather thin, so i was hoping to maybe have a pair. I know that that species hasn't or if then really rarely been bred successfully, but i thought i'd give it a shot (i got them both rather low priced).

I keep them in a 140x50x60 cm sized tank (eheim lights and filtration (the big electronic 3e), so at the bottom limit for that species. They were seperated by chicken wire (stabilized with aluminum bars) from day one. Both have some hiding spots, but the moment they leave these spots the fish will spot each other.

The smaller one was bought on June 1st. Since then, they interact every day the moment they see each other and i believe, they'd try to kill each other but wanted to ask you guys for advice, before i sell one of them.
The seller told me he knows someone who bred h. malabaricus and that the breeding behaviour was pretty messy, meaning that the female ended up with a dislocated jaw and substantial loss at the fins.
The two fish expand their gills when they see each other. The thin one moves in a way that it forms an "S" with its spine while opening its jaw widely. Sometimes, it hovers in the water and "bites some water" (meaning it opens its jaw more or less slowly then closes it rapidly and repeats this several times in a row). Sometimes, air bubbles leave the gills. Both stretch their fins. The bulkier one vibrates its head.
This behaviour is followed by them ramming the chicken fence in between them. I'll try to attach some fotos (sry for the mediocre quality) where you will see the injuries they induce to themselves by doing that and the dents the once straight fence has meanwhile.

I'm brand new to this forum so i can't post links and i don't know how to upload a video otherwise, so for the moment i'm afraid i can't upload a video where you can see some of the behaviour described above. I believe it would help give you an idea of the behaviour and you might spot things i didn't notice.

I'd be happy if someone here has some experience with hoplias breeding or maybe even the curupiras and could help me. Of course, i'm also interested in the opinion of everyone else who has an idea of what "breeding" should look like.
If you have doubts regarding the identification of the species, feel free to express them for i'm not 100 % sure.

Regards,
TheMarburn

 

[tlindsey]

Welcome aboard

Did anyone tell you they were a pair?

 

[TheMarburn]

Thanks!

No. The only information about identifying the species' sex i could find was that the females "are thought to be heavier in build" (from a site called "the wolf pack").
Comparing the two fish in my tank, it seemed possible that the one on the right is a female and the other one is a male. But as far as i know, the precise identification of the hoplias species is quite difficult. Therefore, i can't guarantee that the two fish in my tank actually belong to the same species. So it seems possible that the difference in size is not a matter of sex, but a matter of species.

 

[TheMarburn]

Here's another picture where you can see the expanded gills.

The other ones where ment to help identify the species, but i'm afraid the pores aren't visible.

 

[tlindsey]

I personally never heard of this species being bred in captivity. That could be 2 male or 2 female or male and female but not a pair. You would have to know defiantly if they were a pair. I would personally rehome 1 of them if you don't want to keep them seperated.

 

[kno4te]

Not sure about breeding behavior. However, if similar to mala then the male will have a rounder dorsal fin. The anal fin will be closer to the caudal fin. Males will also have a rounder/hump head shape and slimmer body. I’ve seen breeding mala pairs tolerate each other and not flare at each other.

Would keep separate as behavior isn’t predictable.

 

[TheMarburn]

Thanks for your help, i was afraid you'd say something like that. Too bad it didn't work, would have been nice to avoid wildlife imports. Maybe one day i'll try again with a bigger tank.