S. euptera mating fights?

[L number Banana]

Hi,
Has anyone seen the mating behavior? Is it quite violent?

Here's what I'm observing and this just started yesterday.
Stable cmmunity tank been the same for about a year. No new fish. I think it's 38 gal tall (36 long x 12 deep by 18 high). Water stable, temps stable, no new furniture. 4 Farlowella, 1 small L066(?), 1 P.maccus, many otos, five Cardinal Tetras, 5 Glass cats, and the three 4-6 inch TL synos.

I'm getting them ready for a tank move so I changed some of the water with spring water (10%), fed normally but with a raw tiger shrimp included and added 4 plant bunches still in their pots for the move.

Now the two largest synos are going at each other, sometimes a gentle bump on the side sometimes quite a violent bump. No idea about male or female really but the fattest one has a possible female protrusion????
Haven't seen any bites or scratches. This has been going on since yesterday non-stop. Once in a while, the third one comes over and is chased away immediately by one or the other large ones.

They all have lots of hiding spots in the older plantings but none of them are using them at the moment, they're all out in the open and spending more time than usual just floating upside-down beside each other.

There's quite a few threads here about rough syno activity so maybe it would help us if someone has a good description of the difference between fighting behavior and mating behavior?

[Maccus]

I wonder if yours are large enough to start mating behavior?...I think they need to be 2-3 yrs old to be sexually mature.
At any rate, if there's any fighting related to mating behavior, I would like to know too. Mine suddenly started fighting and have been hurting each other ( probably saw my threads).

Also, cardinal tetras and otos as tankmates for syno eupterus?...I think you are asking for trouble with the adult size of the synos.

[L number Banana]

It was your thread that made me ask. I was on here looking for info and came across a few that are on this subject, mine don't seem to be injuring each other but it just started.

The synos are old enough I guess but just. Not sure how accurate my sizing was... , the largest just got measured when he was resting up against the glass and she/he is 7 inches if you count the whole tail.

I'm not too worried about the little fish, they've been together since the beginning and there's so many hiding places. The otos keep breeding and I keep moving the extras to other tanks, tetras have gotten to a good size but they seem to stay in their group. If the synos eat the little ones some day, I won't be alarmed. They're beautiful and appreciated but I hope I'd notice if that started happening so I could move them out. It's my main viewing tank in my living room so I see them a lot and can keep an eye out for snacking.

At the moment they've gone to their corners, all is quiet. I forgot to mention, I also have three banjo cats in there and now that all the commotion is over, they've just wandered out for a snuffle around the front of the tank. They're small too but have no issue giving the Synos a whack with their tail when the synos come close to whatever they're eating.