I've been camped out on a beanbag in front of the River Tank for the past hour and a half watching this dominant male trying to entice females into his territory.
Earlier today I carried out a small water change (probably only 15% of the volume) and thought nothing more of it. There was not a huge amount of activity going on until after the main lights went off, leaving the blue moon tube on. Anyway, to the upper right hand side of the tank, I noticed this male Sewellia lineolata patrolling an area which comprised a certain amount of one of the big bogwood pieces with Anubias and Java moss growing on it, plus an area of the back glass. He would swim in a loop around this area, and when a female happened to land within this zone, he became very excitable and began dancing in circles around her, fluttering his fins like a butterfly. If she stayed put, he would then nibble her dorsal surface, from the head along to the dorsal fin itself, and then back again, and would repeat this until she decided she'd had enough for the moment. On occasion, following the nibbling, the male seemed to be able to entice her out into the open water where they would semi-entwine, their bodies absolutely rigid as they did so. At first I couldn't see anything being released into the water, but after this was repeated 8 or 9 times, I saw a small cloud of eggs/milt released. It was not a big cloud, but just a small amount. The female then swam off and the male began patrolling his area again.
This scenario was repeated a number of times, and once with a slightly smaller (and obviously different) female. If a female was on the glass within 'his area', the initial circling would take place on the glass, with the male zooming round and round her. If on the wood, he'd swim around her and through the plants if they were in the way, forming a complete circle around her. Then the nibbling would start again - this was in no way aggressive, but actually seemed very tender. Each time the pair rose up and entwined, it happened in a slightly different position within the tank. Each time, their undersides faced towards each other at a slight angle, and they appeared to be almost joined by the pectoral fins on one side of their bodies (i.e. the females left pectoral and the males right pectoral) so that they seemed locked in position for a second or two. It was at this point they 'shook' and I saw a small amount of 'particles' released.
Unfortunately, I didn't get any pics as my camera wasn't to hand and I was afraid my moving would disturb them. However, I hope my descriptions are of some help in identifying their spawning behaviour. I should also mention that this male Sewellia would not tolerate any fish within his territory unless it was a female S. lineolata. His prime target seemed to be to entice a willing female out and up into the open water with him.
Sadly none of the spawns seemed to occur as near to the Eheim intake as I would have liked, but you never know. There is a lot of current in this tank, so who knows where the eggs could end up.
Also, I had a feeling something was going on as I haven't seen my lone Schistura balteata venture out for months, and tonight, he/she was out and about in my full view avidly foraging for something.
I came away when the blue moon lighting went off, but there is a small table lamp on to the side of the tank and there is still a lot of activity occuring in his area, although it is not quite so easy to see. And I've got chronic neck ache from staying in the same place for so long!
Emma
Resistance is futile. You will be assimilated.