Remove One Fish And Suddenly The Cichlids Have Gone Crazy...

[SouthernCross]

So I removed my female salvini as she was just a tad too aggressive and sold her on. Never actually attacked anyone but there was lots of chasing and the fish were never really settled. So I removed her two days ago, and now suddenly all these things are happening in my tank!
 
24 hours later, two of my four rainbow cichlids are seemingly paired up and staked claim on a corner and look like they are in love.
 
48 hours later I've come home and now my two blue acaras (who have co-existed peacefully for months, one is about 4.5 inches and the other would be pushing 6 inches) are liplocked and they have been liplocked and battling for what seems like hours. They are really starting to make a mess of each other's mouths.
 
They are mostly doing it in the corner that my rainbows picked out last night too, so Mr. Rainbow keeps swimming in there trying to play referee (and probably trying to get his corner back) and getting slammed out of there. He and Mrs Rainbow have kind of lost their corner though so they don't look as into each other as they did yesterday.
 
I even tried putting food in there, and nothing is stopping the acaras!
 
I've done a bit of googling, and I'm guessing what I'm seeing is either pure aggression (maybe trying to establish a new boss fish?), or they have decided to get frisky too and this is them 'testing' the strength of their potential mate and provided they dont kill each other, they might spawn soon? I had noticed the bigger one 'shaking' at the smaller one a fair bit over the months but nothing ever came of it. Has anyone had this happen before? How long do they fight for? I'm just worried about the damage they are doing to each other's faces. Lots of scales off, and one of them has a bit of a wonky mouth anyway and I'm worried he might get his jaw broken.

 
Can cichlids do this, where a 'threat' is removed and suddenly they all think its safe to have babies?
 
Thought I'd attach some pictures too. Excuse the water in the acaras picture, took this after I tried to distract them with food.
 
Acaras:

 
Rainbows - I don't know what is so special about that corner!

 
 

 

[star4]

Try re-arranging the whole tank, the loss of a dominant fish can cause problems.

 

[DrRob]

Indeed, 100% with star4, removing the Salvini was a good idea but a new pecking order is now being established.

 

[SouthernCross]

I thought that might be part of it - I'm planning to do a water change before so I will move some things around. I have one huge piece of wood that runs the length of the tank that can't really go any other way, so it will have to stay put and I'll just move the smaller things.
 
Its so bizarre, all these fish were together in the tank BEFORE I even had the Salvini, and there was nothing like this before!
 
What do you make of the sudden 'breeding' behaviour when there was never any sign of it before?
 
The four rainbows I have used to school together all over the tank. Tonight, the male who 'won' the female is now showing aggression to the other males (I turned out to have one female and three males).

 

[star4]

What size were the fish before you added the salvini? it could be they were not mature enough to breed, although if my memory serves me right BA will breed at about 2-3", but dont quote me on that lol. The salvini being a pretatory more aggressive fish has stopped any breeding due to it not being worth their energy as they would not be able to protect the fry - this is just guessing BTW no scientific proof

 

[eaglesaquarium]

Indeed, 100% with star4, removing the Salvini was a good idea but a new pecking order is now being established.

 
 
Exactly as DrRob states.  This is 'normal' behavior for these fish.  The dominant fish actually keeps a lid on the aggression.  Removing the dominant fish creates anarchy until a new dominant fish can be established.  Wolf packs work in a similar manner.  As long as the alphas are in place, the pack works in harmony, with a bit of squabbling.  Remove the alphas (m/f) and a new one must be established and there's an outbreak of aggression, which normally subsides once the new alpha is established.

 

[SouthernCross]

They were all pretty big... not juveniles by any means. Had them all a couple of years. 
 
The salvini was one of those experiments I decided to try and it turned out it really didn't work in the end. Probably had her in the tank no more than six months. I was lucky there were no injuries/fatalities, but as I said, she just stressed the whole tank out too much and whenever she swam by all the other fish ducked for cover! They knew she was boss.
 
Until now....

 

[star4]

Ah then they had already established a pecking order before the addition of the salvini. I do see this quite often in my tanks when I rescue fish and add a newcommer that doesnt fit in and I have to remove it again. It should settle back down again, 6 months in a fish lifetime is a long while and whoever was "boss" before has now lost that position. A good re-arrangement of the tank should help.

 

[SouthernCross]

Yep, the thing that has me really baffled is these rainbows pairing out of the blue though! As I said, had them for years, all,four used to school together....I had all but given up on getting a pair, and I always used to comment on what nice easygoing cichlids they were!

 

[star4]

Rainbows can be little monsters! mine (called Rambo) attacked my oscar, attacked severums he now lives with Urau and he will go head to head with the largest one with no fear.