Ok so I have 3 angles a friend gave me, they seemed to settle in okay. he mentioned they chase each other sometimes ect and they have been doing that to a certain degree, nothing to serious.

Until last two days, They have been fighting quite hard. Locking mouths and tugging back and forwards. It is now pretty much non stop.

Not really sure what to do.

I have no idea if they are males or females.

I can put one in a 50L for a short time to see how they go but that seems to small even for one of them.

It does seem to be two picking on one but hard to tell as they move around so fast.

Any advice would be great.

i found when they are bigger the males have a bump on there head, maybe you have a pair and an extra male

If they slow down for a minute or two, you could try and sex them and check if it's a couple of males that are doing the fighting, (what I'd expect), it's been a while but I believe the females have a more rounded ovipositer, while the guys have more pointed bits.

I'd try and find another female angel roughly the same size as your three and see if that reduces the fighting. They do like to be in pairs, and I've seen a couple of males hanging out together happily, so maybe the gender of the fourth won't matter so much...

Or, you could rehome one of your three. Wet Pets usually take unwanted fish if they have room.