Sex And The Single Sewellia

[Martin Thoene]

Ok, OK....I know I've been a bad boy today regarding thse guys. It is April 1st after all

Anyhow, I did remove the slate from the tank and replace it with another algae covered pebble, plus I did a water-change on the tank also. While looking at the fish, I noticed something that initially alarmed me. Bear with me.....look at these pictures carefully. Look at the first few pectoral fin rays particularly.......

Munching on the algae pebble.....




Lounging on driftwood.....




Nothing particularly unusual.....



Front edges look smooth in this pic....



Different fish.....still nothing out of the ordinary......



Another fish.....look carefully at this one's fins......



Looks different eh?
I was looking at the fish I have always felt was a male because of its somewhat slimmer appearance. I got a shock. I thought I could see a fungal growth on the leading edges of the pectorals, but kind of "on top" of the fin......like so.....



Note tubercules around leading edge of nose....



Trick of the light....up close it looks like this...





Almost like the rays are somehow raised up off the fin compared with all the other 4 fish.
Here "he" is sitting with another one.....



This is the killer shot that really shows the difference in the fins.



It looks as though there are some raised tubercules near the fin base at the front. This would be consistent with tubercules mentioned in the original description as a characteristic of sexual dimporphism. Other factors are to do with more minute differences of tuberculate sizes.

So....based on this fish's appearance being different from the other's and my experience with sexual dimorphism in Pseudogastromyzon cheni, I have to conclude that this is probably a male, and the fact that it is showing sexual characteristics certainly raises the possibilities of these guys breeding. Having a male and 4 females would be quite a sweet combination. It's possible of course that some of the others might be immature males not showing any characteristics, but their slight extra plumpness leads me to doubt that.

Fingers crossed......

Martin.

[Jim Powers]

Fantastic shots!! And very enlightening too.
Its also very encouraging to see those characteristics develop.
Did you notice any of these when you first got the fish or have they developed recently?
Of course you know, if spawning does takes place, you are going to have to REALLY convince us.

[Emma Turner]

Gah! Just typed out a reply, and the site went offline!

Anyway, that is most interesting, Martin. Your "chap" looks a bit like this "chap" that I photographed at the shop a little while back. I'm not sure if he's one of the ones that ended up coming home with me, but nevertheless, you can clearly see the raised areas on the front of the pectoral fins:


My lot have been very active today, this has been since I carried out a larger than normal water change earlier on today, with RO water that was cooler than the tank water (I had lots of spare RO to use up). I also cleaned out the powerheads very thoroughly too, as I hadn't really done this for a while. The increased flow/aeration and the cooler temps seems to have caused both the Sewellias and the Schisturas to become very exciteable, and there has been lots of playful chasing around. I actually saw one of the more dominant Sewellia go for my large Annamia specimen today, which is the first time I have ever noted any aggression between them. The Annamia is lovely, always present and very peaceful. All of this playfulness and chasing is very very quick though, far too quick for me to capture on camera anyway! It makes me wonder if they would actually prefer a cooler temperature to what I currently keep the tank at (78 deg), as there is certainly a huge difference in behaviour.

Emma

[Martin Thoene]

No Jim, I only noticed this today. The "fungus" appearance was quite noticeable and I thought it was divine retribution for my joke
It's weird, just at certain light angles it looks like that.

Took me flippin' ages to get pics of the guy. The others are much less skittish than him. He steadfastly defends his centrally placed rock against all-comers and has always been the most aggressive of the 5. Biggest too.

(EDIT) Oh Emma! Incredible picture. It's about here the limitations of my camera are reached. That pic really shows the raised parts in a clearer way, plus the nasal tubercules are visible too. Nice pic of a nice fish. Aren't they just fabulous?

Martin.

[Emma Turner]

Martin, I've only just realised that you'd added to your message (I thought you hadn't noticed that I'd posted that pic on Sat, as we all seemed to be writing at the same time there!).

I was rather lucky with that photograph, as the Sewellia had chosen to rest immediately behind the front glass of the stock tank.

I've had a closer look at some of the ones in my tank at home, and although I haven't been able to see all six at once, at least three of them have the little ridges on the pectoral fins. It's be interesting to know if you've managed to observe any more on any of yours, and from anyone else who keeps them too (Gary?). What size are your specimens, Martin? My lot are approx 6.5cm, and Gary's will probably be about the same as he got them from us.

Emma

[Martin Thoene]

That's funny! I wondered why you hadn't added anything since. Yes, I posted and also had server problems. Mine accepted, then I found you posted simultaneously, so added an edit.

Anyhow.....my fish are smaller. Probably 4cms and the "male" being about 5. I managed to get these pictures of him yesterday. A strategically placed slab of algae-covered slate makes for a great photographic posing place for these guys. You'll progressively need sunglasses


You can really see the raised parts of the first few pectoral rays.


Now the pictures get all "Arty"......










Martin.

[Gary Herring]

It's be interesting to know if you've managed to observe any more on any of yours, and from anyone else who keeps them too (Gary?). What size are your specimens, Martin? My lot are approx 6.5cm, and Gary's will probably be about the same as he got them from us.

Very interesting thread!

One of mine is about 5.5cm and the other about 6cm. I hav'nt been at home a lot in the last couple of day's so i've not yet been able to have a really close inspection for those fin ridges, but i have had a quick look and neither of mine appear to have them. I will have a better look later on today, particularly at the larger of the two as he(?) is definatly slightly less plump than the other.
Good luck to both of you (and anyone else) in trying to spawn these beautiful fish, it would be fantastic if it happened. Sewellia seem fairly simular in charictor and activity to P. cheni, so you never know.
By the way, has their been any known capive spawning of any other balatorine species, apart from cheni?
And what do you consider to be the optimum ph and hardness levels for hillstreams?

[Martin Thoene]

Gary, somebody in Germany bred Liniparhomaloptera disparis disparis a few years ago. So have Jim Powers and myself, in fact we co-wrote a two-part article on that which was published in the November and December 2002 editions of FAMA magazine.

I think the subject of water parameters is a difficult one. Balitorids are fairly widespread and I'm sure the geology of their rivers varies quite a bit. This will have an affect upon hardness and pH. I actually believe that they're probably pretty adaptable due to small, high flow streams being subject to flash floods, run off from land, etc that would probably affect levels more than in a much larger, downstream river.
Change may actually be the trigger needed to kick off spawning. Certainly my cheni first bred successfully after moving here from England, living in a small holding tank for a while and then suddenly finding themselves in a new 65 gallon River-Tank. I had babies 2 weeks later! Toronto water is generally around 7.6 pH.

I can check my tank parameters tonight if you're interested. Actually, it might be interesting to know what other's tank parameters are also. See if there are any vast differences.

Martin.

[Gary Herring]

Martin,

Yes actually i remember reading about L. disparis in your article. I was thinking more of the suckerbelly types such as Gastro's, Beaufortia, etc. Im assuming that no spawnings have taken place that we are aware of, but have you seen any behavior in these types of fish that leads you to believe it is at least possible? I suppose partly what im trying to get at is, why is it that the captive spawning of cheni is a definate possibility when it appears not to be in other simular species? I thought (perhaps wrongly) it may have something to do with the fact that they are more active and adaptable than others, therefore the ordeal of shipping and having to settle into numerous new environments perhaps damages them less than say, a Beaufortia. As Sewellia seem quite simular in respect of their adaptability and outgoing personality, hopefully they will be simular with regards to the possibility of breeding as well. Time will tell!

To be honest im probably slightly over-obsessive when it comes to water parameters. I remember your article (and Don Joku's) mentioned soft to medium hardness with a slightly acid ph, so becouse my tap water is very hard and alkaline i use partially re-mineralised RO water and keep both KH and GH at 3 degrees and ph at 7. I would definatly be interested to know what your parameters are, as well as anyone else who has had breeding success with Hillstreams.
All this talk of breeding is probably pretty academic to me at the moment anyway. I've only got two Sewellia's, plus i doubt my 30"x12"x15" river tank is spacious enough. If i get my way im planning on setting up a 6 foot river tank later on this year, so it might be more relevant then. Help! I think MTS is setting in! Resistance is most definatly futile.