1. While many kids are lucky enough to become the best of friends with their siblings, it's common for brothers and sisters to fight. What usually causes this?
In my opinion the best-of-friends –kind of siblings are very few and far between! It is not until much later, I find, that brothers or sisters start getting a long better. And unfortunately, some never do. I have clients who haven’t spoken to a sibling in years!

With regards to what causes it? You name it and it can be the cause of an argument or a fight; be it toys, friends, clothing; a lot depends on the life stages of the children involved. 

Between 18 months and 2 years old, for example, a child has a deep seated need to do things for him or herself, and if an older brother or sister, who wants to be a good helper and who wants to do everything for the younger one then comes and interferes, that could cause a lot of frustration-on both sides.

And so we can go through all the different stages of life and have a number of situations that could cause rivalry. 

Sometimes though, it is pure personality clashes that cause the friction between two children, so that as well has a very definite influence.

2. Could parents treating their kids differently also have an impact?
Most definitely yes,
Labelling is one example; if parents label the one child as the little angel who can do absolutely nothing wrong, and another one as a problem child, or even just as the one who needs a little more attention etc., that could cause a lot of rivalry between children. 
Being unfair as well – if one child is allowed certain things that another one is not, or if one child can get away with murder and only gets a warning as a result thereof, but another child gets punished harsher for the same behaviour or incident, that will make a child feel un loved, and emotionally unsafe. And one reaction could be to lash out at the sibling because of these hurt feelings being caused.

3. As a parent, what should I do when the fighting starts?
Difficult question because it so depends on the situation, the age of the children involved and so forth, but basics would be to not get overly emotionally involved. In other words – stay calm! Now, after a hard day’s work at the office, this is way easier said than done!! But try to not scream and shout and start handing out slaps left and right, because you are doing nothing to help or better the situation.

Acknowledge and validate each child’s feelings; for example “I can see that you are extremely upset.” Immediately this kind of relaxes the child even if it’s just a little, because I don’t have to explain to you what I’m feeling or experiencing. And this is one of the tools you use if you are communicating healthily and effectively with people, so this is just one of many situations where you can start teaching your children to communicate better.

You create a calm atmosphere, where you guide them into talking about what happened, giving equal time to both to explain their side of the situation.
And then – importantly – try to involve them in finding a solution to the problem. So clarify the problem in simple terms for them – for example “okay, so you both would like to play with that specific doll” and then ask them “what plan do you think we can make to solve this problem.

Let me just say that this takes a lot of practice and a lot of patients, but no one is perfect and the mere fact that you are consciously trying to implement this is already worth a gold star in my books!
And if you succeed, you’ll not only diffuse the current situation, but also teach them how to handle situations that might arise in the future.

4. Some believe “not getting involved” as a parent could also help – what's your take?
I do believe that in some cases this approach could be beneficial, because you allow your children to navigate through it themselves, which in itself has a lot of value, but I think it hugely depends on the age of the children involved. For older children this might be a useful way in dealing with it, but for younger children not so much. I think if you withdraw completely, you are not utilising the teaching opportunity that such situations create…

5. When should I start thinking about getting professional help?
When what you've tried has not been working for you, and as a result you feel like you are going crazy – remember that siblings will fight, that is 1005 normal. Mine are now 2 and {97fa4f7e3f90de63208dbf923bf7383c3bb584adf96b64fde63584d1e00110d6} and someone once told me that when he had a child, he became a parent, but the moment he had a second child; he became a referee…
Sometimes if you really struggle to get it under control, it might be helpful to get some parent counselling – some objective ideas and advice on how to handle your specific situation or to take your children for a play therapy session – sometimes kids are overly aggressive or irritated, because there is a deeper underlying cause, and through a play therapy session, this could be identified and addressed.

6. Any useful tips for parents to keep the peace in the home?
You have to try and stay objective and calm. 
Be fair, so what goes for one, also goes for the other. This also creates a clear set of boundaries which makes a child feel emotionally safe. And here it’s important that both parents are on the same page with regards to discipline for example – and this is best achieved via healthy and effective communication
Validate your children’s frustrations and emotions and involve them in the solving of their specific problems in order to help equip them for future situations.