Agressive Yoyos???

[stormycat]

Hi
I have had my tank for 2 years now. I have 15 yoyos, 6 polkadot and 4 striata amongst soem other fish. Everything has been fine up until the last 2 days. The yoyos have started being really agressive towards each other. I know they can have a little fight now and again, but this latest behaviour seems really extreme. I would say it is about half of them that are being agressive and skittish towards each other.
Any ideas?
Thanks

[Mad Duff]

A little bit more info about the tank may well help a lot:

How big is the tank ?
How big are the fish ?
What to you have in the tank by way of decor and hiding places ?
What are your water parameters - ph, nitrate, nitrite etc

Yoyo's can be particularly feisty towards each other certainly from my experience this aggression can be worse in very small groups or very large groups, I have 7 at the moment and at pretty much the same time each night the little skirmishes start around the tank and it is only among the Yoyo's.

[shari2]

I had noticed that when my female became gravid the skirmishes became nearly constant. Got any fat fish?

[Batch]

I have 9 yo-yos in my 55gal.

Everybody has been mostly peaceful for the last couple of months, but
there have been times when they went at it for several days, then calmed down again. I have no real idea why.

Batch

[stormycat]

The tank is 400 Litres - a 5ft Jewel
on average the fish are 2 inches - some a bit smaller some a bit bigger
plenty of furniture, hidinbg places and plants
ph is 7.2
nitrates a little higher than we would like - in the process of getting it down
all other tests normal
did a full test on the water last week ntrites, ammonia etc


yes i have got a few fat fish!!!

just got in from work and looking at the tank now - they do seem a lot calmer than they were and the colours are ok
the last few days some of the them were really grey - not nice to see

[newshound]

loaches will battle from time to time. the closer the match the longer it takes for things to settle down.
yoyos can get large so it is nice to see them in such a big tank (400L approx 125 gallon?).

[stormycat]

Not sure on US gallons, but I know it is a pretty large tank

Thanks for all the info.
They do seem to have gone back to being themselves now, even though it took a good few days.