I had a fortunate chance to witness this behaviour other day.Funniest part is that i didn`t do anything that could be considered as an purpose.I removed plecos and five Distichodus affinis to a show held by our aqurium society.Same time i took few wood branches away and left the tank a total mess.Water level was half of what is normal.So Synodontis had very few hiding places and i took also a powerhead(Aquamedic 3500l/h) away as well.The next day they were very active which they didn`t have done past ½ year of hiding.All males swim after females and vica versa.the next day there were several bite marks on their backs after restless nightAs has been noted here, there were no eggs produced, but I do still feel that "sex" was on the minds of the fish...esp. the males...in that the amplexus behavior (males head wrapping on the females...kind of like T-position in Corydoras, but with a flexible fish) was very evident. This behavior is actually quite common is many catfishes.
I noticed that temperature had sunk to 22 celsius from 25.Light were on in daytime and males were tryin do something in that t-position it looked more like this -) just more bended.I didn´t too noticed or found any eggs.Females didn`t show to be ripe with eggs.I must try to continue to do some serious efforts with this species.I think that the trigger in this case was sudden drop of temperature.Any comments?