WE originally had 3 clown loaches but sadly 2 of them died after a year - leaving one. Now this one has been on its own for about 6 months and looked quite ok with it. We were told at a fish shop that loaches, although sociable, can manage on their own.
Now recently we were told that clowns really do enjoy the company of others, and can even be depressed if on their own! So late this afternoon, we got 2 more - both about the same size as our old one.
They got on for about 2 mins. Since then the old one has been fighting the new ones - chasing them about and even trying to bite them. (There are no external marks that I can see at this time). Obviously though there must be quite some stress.
So far I have added food with no benefit.
Are they going to get over this once territories are established? Or is it hopeless, and the best thing is for them to be separated tonight (via a large 6litre floating bag in the tank - I do not have a proper quarantine facility

PS my tank is 180litres with lots of silk plants and a rock arch and 2 caves.
Thanks
Titus