Out of sudden every Oscar and every Gourami of mine start bullying at one Gourami
it's 7 VS 1

they chase away the others sometimes, not chasing it around the tank, but as for today out of sudden it happen the only fish which are not involved are the pleco

had anyone seen this happen? how and why?
they had been together for a month or more though they started to get along.

luckily it happen on Sunday today I have been watching and now the Bullied Gourami staying with my Hujeta was stress earlier but is eating now and destroying my plant

wouldn't it be great to get into the mind of a fish? As to why your Oscars are suddenly ganging up on the other fish is something I really cannot say. The aquarium is a compromise remember, so this behavior may be completely different to what is in the wild, aquarium Fish are forced to live together, in the wild they can avoid each other.

The only advice I can give you is to remove the fish that is getting bullied before it ends up dead

yes it is removed, and yes the large tank will reduce this from happening, it's hard to accomplish what I wanted, having to put them all together looks nice!!!
getting more new tank tomorrow. getting the tank ready to deal with this problem.

how nice if they can all be together. may be they mean to be lonely
still glade that Oscars are still getting along. it'll be sad if they were to move to individual tank

that is the best move you did. Normally, the weakest specie or those that had
some issue is always a moving target... as explain to me by my late father,
sick fish is always the first target and normally end up that way..bullying

does not look sick, that happen just about an hour before feeding and gourami was eating a lots, in the tank Oscar are the dominant, left with 4 gourami between this 4 gourami this gourami is normally second in big bully list. but normally they don't go so extreme

best I can do before it got killed, just worry that this is just the beginning till all fish have to be moved to their own place

in the farm, any single fish that get hurt or who develop rotten fin
or any sign of sickness will be surely a target of attack... i don't
have scientific explanation about it but that is what we believe in
the fish cage or pond.... and once we see one being bullied, we get
ring net and scoop them out including those attacking it and dispose
it so that it will not spread any possible disease/s .

the gourami which are removed are now very active and eating lots of bruise but not stressed, hopefully all turn out ok, thanks for the information!!!

nice to know he is doing well... take note, as i have said, it is our
primitive way of fish keeping, no scientific explanation but that is what
we do in the event we see bullying in the fish cage farm or pond.

well, I just had to move my Tiger O to a different tank. My lutino and my baby RD were making him miserable. He fought everyday, and when he didnt fight he was forced into the same corner over and over again. He could never come out with out fighting and once he actually started standing up for himself, I thought that he would be alright, but I was dead wrong. It got so bad my baby RD began to go into the hole that he was forced into and peck him into a different hole. Poor thing never could swim about like a normal fish. Now I have him with my JD and they both ignore each other, mainly because the JD stays in a cave and is much smaller, but then again size doesnt matter, my small GT used to punk my Tiger who is three of four time her size.

I dunno what was going on by my lutino was almost having the RD like a protege (i know they dont do that for real but it is the best comparison) and he would referee the assault on the Tiger. Poor Tiger got some of his manhood back in the other tank stares at the back of it and sometimes tries to attach himself, must make him feel tough now that they are gone He is back to swimming around like a normal Oscar should!

in your case, it is more on territorial issues... or dominance...
not all fish are ganging on him but only one fish....

it started as only one fish (lutino) and then once I guess everyone saw how he was he became an easy target for everyone to bully. I know it has to be dominance because he would attempt to fight back and was just a weak link in the fight. His spirit was so broken he just gave up!

They just hated to see him period. and you would think in a large tank with only 3 fish, they might be able to stand eachother, but not so much..my lutino is just extremely aggressive and as they get older, I have been looking at the genitalia, and I think my lutino is a male and the tiger is a female. I see differences and have researched how they are supposed to look. I already know the RD is male too. Getting older is the biggest problem though!

mylutino your fish are more extreme you should had taken action earlier, cos action taken earlier will leave them less stressful get back on their stance faster. it's always sad to see this.

sometimes size matters, where as if my Oscar are same size of my gourami, the gourami will be living in hell, a 3 inch Oscar can chase 5 inch gourami away. may be that's because Oscar have a bigger mouth that gourami afraid of them lol