Synspilum aggression advice

[abseedy]

Hi, was hoping to get some opinions and/or advice on my latest tank issue.

We have a 6ft tank which currently has 2 oscars, (about 7 and 10 inches) 3 largish silver dollars, 1 female convict, 1 Pundamilia nyererei and one synspilum (about 10 inches). I don't know what sexes any of them are (except the convict).
It's an established tank of about 4 years and the Synspilum and the Pundamilia nyererei were the newest editions about 2 years ago (when synspilum was about 4 inches). Big Oscar has always been the boss and all has been peaceful between these particular fish. However, Synspilum is now a lot bigger and has recently started attacking the smaller oscar, nipping and chasing. I have temporarily removed synspilum from the tank in order to protect small oscar but I wanted some advice towards a permanent solution. If possible I want to avoid getting rid of spynspilum as I really like the fish.
I'm not totally sure what the behavior is as synspilum isn't competing with big oscar and is still submissive towards him/her. Synspilum is just bullying smaller oscar. Maybe just choosing it's battles and only going for fish slightly smaller. It hasn't shown aggression to any of the other fish though. Only small oscar.

Has anyone had any similar issues with synspilum? did you find anything to make the aggression subside? I read somewhere that aggression can be avoided by having a pair instead of a loner. Anyone heard anything about this? I realise it would be difficult to pair it up considering it is a large adult fish but maybe a potential solution.

Thanks in advance for any help.

 

[dan518]

I think you will find as soon as the synspilum is of equal size too your larger oscar he will start attacking that as well. Personally I think that once a fish wants the entire tank as its own there is very little you can do,

 

[duanes]

I agree with Dan, and that the synspillum/melanurum although not aggressive (compared to most North/ Central American standards) will always be too much for the oscars, or most other South American's, and eventually if kept together take both (assassinate)the oscars out.
It seems obvious to me that the Mexican sees a 6ft tank as only enough space for itself, but no other similar shaped, largish species.
To me, only something in the size of 300 plus gallons is large enough for a community with any Vieja species of any size. A 6ft tank is probably OK for a pair of Vieja and some others.

 

[jaws7777]

Same as the others. Unfortunately that tank is overstocked the syn doesnt seem to want to share.

Oscars or syn will need to go.

 

[abseedy]

yeah gunna have to admit defeat i think, he's definitely in the 'I want the tank for myself' faze Thanks for the advise guys