Sexing Sewellia hillstream loaches

V1K

Member
I have 5 Sewellia lineolata and 1 S. SE01, I was wondering if anyone has a good eye for sexing them. 1-3 are with me for 3 months. 4-5 I only got a week ago, but the guy at a shop told it's the same batch as my previous ones, although these 2 are much smaller. 6 is the Sewellia SE01, and it also have been in my tank for 3 months (no belly photo as it doesn't like sitting on glass as much as the lineolatas). None of them have so called fences, as far as I can tell.
1. Bai (strong suspicion this is a girl)

Bai.JPG

2. Hei

Hei.JPG

3. Sec

Sec.JPG

4. Cas

Cas (1).JPG

5. Din

Din (1).JPG

6. Dax

Dax.JPG
 

mimo91088

Member
Following because I'm still unclear myself!
 
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V1K

Member
mimo91088 said:
Following because I'm still unclear myself!
Seems like everyone is unclear :confused:...
 

mimo91088

Member
I still don't even know what the fences are lol
 
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V1K

Member
mimo91088 said:
I still don't even know what the fences are lol
I believe you can see them in these photos, on the pectoral fins close to the head, sort of fuzzy bumps. Mine don't have them, but it seems statistically improbable that all 6 are girls, so maybe they're just immature.
 

mimo91088

Member
I had similar thoughts as well. I wonder if it's similar to breeding stars on goldfish and they're only present sometimes? I have 7 SW01 and I haven't seen that on any of mine either.
 

Skrabbitskrabbit

Member
I found this video that may help
Sexing sewellia
Screenshot (from video) shows the pair she was comparing. Female is bigger, has wider head and body regions, and the shape of the fins more round if I understand correctly
83D872AB-260C-434C-BDB1-56DB9C702A43.jpeg

if I had to guess I’d say your girls are 1,2, &4
Boys 3&5 ?? 6?? Who knows. Keyword is guess!
Edit to add : I’ve never seen fences on mine either...
 

mimo91088

Member
I'll have to check that video out later!
 
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V1K

Member
Skrabbitskrabbit said:
I found this video that may help
Sexing sewellia
Screenshot (from video) shows the pair she was comparing. Female is bigger, has wider head and body regions, and the shape of the fins more round if I understand correctly
83D872AB-260C-434C-BDB1-56DB9C702A43.jpeg

if I had to guess I’d say your girls are 1,2, &4
Boys 3&5 ?? 6?? Who knows. Keyword is guess!
Edit to add : I’ve never seen fences on mine either...
Yeah, I've seen that video, as well as a few others. All of those seem to use extremely obvious cases, while mine come somewhere in between. None of mine come even close to the appearance of the male in the screenshot, and look much closer to the female. Maybe they all are - unlikely, but not impossible I guess...
 

Mudminnow

Member
I'm no expert in this either. But, to me, 1 seems most like a female. 3 seems most like a male. But, after looking at some other online pictures, I am leaning toward thinking your fish may be female. Although unlikely, perhaps you have 5 or 6 females.
 

Skrabbitskrabbit

Member
Yeah it does seem like they used the most obviously female/male pairs for the video. I also remember reading that males have a more pronounced coloration. Maybe as they grow, the differences in size, shape, color etc. will become more apparent.
 

Skrabbitskrabbit

Member
I got this picture today of 3/4 of mine... #4 is not pictured and is very much smaller than these 3 right now

1F5E3168-CA33-43C6-A351-74F67B928260.jpeg

My guess is that the boy is the one in the middle (with the broken fin).
The bottom (girl?) is the largest of my group (though hard to tell from photo angle) and the top/left fish is the tank boss and alpha (is the alpha typically female??)
 

mimo91088

Member
Skrabbitskrabbit said:
I got this picture today of 3/4 of mine... #4 is not pictured and is very much smaller than these 3 right now

1F5E3168-CA33-43C6-A351-74F67B928260.jpeg

My guess is that the boy is the one in the middle (with the broken fin).
The bottom (girl?) is the largest of my group (though hard to tell from photo angle) and the top/left fish is the tank boss and alpha (is the alpha typically female??)
I'm still not confident, but I'd agree with your assessment. As for dominance structure I have no idea. I can't tell mine apart as individuals to even tell IF there's a boss.

V1K Skrabbitskrabbit Do either of your's set up little fighting pits and chase each other in a circle for seemingly forever but never actually attack each other? Mine will literally do this for like 30 minutes sometimes. Trying to figure out if that's a dominance thing or a mating thing.
 
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V1K

Member
mimo91088 said:
I can't tell mine apart as individuals to even tell IF there's a boss.
I guess it's harder with spotted, as they don't have intricate patterns... Lineolata are like living Rorschach tests, makes it pretty easy
mimo91088 said:
V1K Skrabbitskrabbit Do either of your's set up little fighting pits and chase each other in a circle for seemingly forever but never actually attack each other? Mine will literally do this for like 30 minutes sometimes. Trying to figure out if that's a dominance thing or a mating thing.
They do, but it happens mostly at feeding time, so I think it's competition, not mating. Here's mine fighting after I gave them some peas.
Skrabbitskrabbit said:
I got this picture today of 3/4 of mine... #4 is not pictured and is very much smaller than these 3 right now

1F5E3168-CA33-43C6-A351-74F67B928260.jpeg

My guess is that the boy is the one in the middle (with the broken fin).
The bottom (girl?) is the largest of my group (though hard to tell from photo angle) and the top/left fish is the tank boss and alpha (is the alpha typically female??)
I think top left is male because the head and pectoral fins meet at sharp angle.
 

mimo91088

Member
Mine fight like that too, but I'll try to get a video of what im describing. It's like a little full speed whirlwind. They don't stop and try to top each other. It leaves little circle impressions in the sand lol.
 

Skrabbitskrabbit

Member
V1K said:
I think top left is male because the head and pectoral fins meet at sharp angle.
honestly it probably is, after watching more YouTube videoso_O it does seem like males are the ones that are territorial so I’m probably wrong :confused:
The funny thing is that I bought 2 different pairs from the same seller and the alpha ended up being one of the two new fish (previously it was the broken fin fish).

mimo91088 said:
I'm still not confident, but I'd agree with your assessment. As for dominance structure I have no idea. I can't tell mine apart as individuals to even tell IF there's a boss.

V1K Skrabbitskrabbit Do either of your's set up little fighting pits and chase each other in a circle for seemingly forever but never actually attack each other? Mine will literally do this for like 30 minutes sometimes. Trying to figure out if that's a dominance thing or a mating thing.
Mine have yet to mate that I can tell (only been in my tank since December) but it sounds like it may be mating to me
 

mrsP

Member
I have breeding Sewellias in my tank, I bought 6, and now I have something between 20 - 30 of them, all sizes. I would think that nr 1 and 3 are females, 2, 4 and 5 males, nr 6 no idea. However, that's my best guess, not definite. Just keep water extremely clean, but don't clean glass too well to provide them the aufwuch layer to eat, they love that.
 
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V1K

Member
mrsP said:
I have breeding Sewellias in my tank, I bought 6, and now I have something between 20 - 30 of them, all sizes. I would think that nr 1 and 3 are females, 2, 4 and 5 males, nr 6 no idea. However, that's my best guess, not definite. Just keep water extremely clean, but don't clean glass too well to provide them the aufwuch layer to eat, they love that.
I clean front and one side glass regularly for viewing, the other side glass just once in a while when it gets extra gross, and I haven't cleaned the back glass ever. Ironically, they mostly hang out on the clean glass . They graze on all sort of surfaces all over the tank, stones, driftwood, even plants. Not sure if my water counts as extra clean or not - on one hand, its nitrates are always so low I actually add them for plants, on the other hand with barbs around there's always some organic mulm present. However, yours lived with notoriously messy goldfish and were fine, so I guess it's not really a problem?
 

mrsP

Member
V1K said:
I clean front and one side glass regularly for viewing, the other side glass just once in a while when it gets extra gross, and I haven't cleaned the back glass ever. Ironically, they mostly hang out on the clean glass . They graze on all sort of surfaces all over the tank, stones, driftwood, even plants. Not sure if my water counts as extra clean or not - on one hand, its nitrates are always so low I actually add them for plants, on the other hand with barbs around there's always some organic mulm present. However, yours lived with notoriously messy goldfish and were fine, so I guess it's not really a problem?
I would imagine it's not a problem, goldfish were REALLY messy, you're absolutely right! I think it's more about water quality, because every natural environment would have some mulm in it.
 

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