My fish have turned aggressive

[nemo69]

My fish are really starting to act agressive to each other as well as towards me. The two clowns use to always hang out beside one another, and now one is kicking the others guy butt and making him hide in the rock work. The blue damsel will nip at anything that goes around him, including my big hand.
Everything use to be more settled and in harmony but they have just started to fight each other.
Does anyone know what may be causing this new behaviour, and if there is anything I can do to change it?
Just for interest sake, here is my tank information.
I have two clown fish, one electric blue damsel and a coral beauty.
We have two cleaner shrimp, a bunch of snails and crabs.
We have a torch coral, blue zoas, hammer head coral, a merulina, and a branching cyphastrea.
The tank has been running for almost two years.
Our water quality:
PH: 8.1-8.2
Nitrite: 0.1
Nitrate: 20
Salinity: 35
Gravity: 1.028

 

[scottyk18]

Damsels are notorius for turning aggressive, as for the clowns... thats beyond me. You might throw a third clown of relative size into the mix. That may deter any territor issues they are having.

 

[sharkboy13]

Originally Posted by scottyk18
You might throw a third clown of relative size into the mix. That may deter any territor issues they are having.
and cause hundreds more....

 

[firefish9]

Move the rockwork around clowns and damisls are from a same family so they are all aggresive if you move the rockwork they will have to find new terriotory.

 

[scotts]

When did you get the clowns? Did you get them together and were they about the same size? What is probably happening, depending on the anwers to those questions, is that they are doing the dominant game. With Clowns they are all born male. Then when you have 2 clowns in a tank and they grow up one of them will get bigger and change into a female. This will be the dominant fish.

 

[rbaldino]

How big is the tank? Could be they've all just gotten bigger and are now feeling more crowded. Everyone knows that damsels can be aggressive, but clowns can be too, especially if one of them has decided to lay claim to something or some spot in the tank.