Urgent advice needed

[JuniperNarni]

A family member has rehomed a dog privately from a friend. On neutral grounds the meeting were fine between new dog and resident dog.
New dog has been growling at resident dog for a couple of days and has escalated to an attack.
What do they do? Currently can not get in touch with previous owner. No rehoming centres to make sure she gets the treatment and care she needs before rehoming. What do they do?

Contact a breed specific rescue, that way the dog will go into foster care and be thoroughly assessed before being approved for rehoming. They are easy enough to find online.

If it's a spaniel I'm a member of several groups if that helps.

In the meantime, completely separate the dogs to keep them both safe. Be it stair gates or a crate.

Keep the dogs separate within the home (use baby gates etc) and walk separately until a more permanent solution can be found.

Are they wanting to keep the new dog? If so they'll need help from a qualified behaviourist who uses positive reinforcement (avoid anyone who advocates pack leadership / alpha dog / dominance theory like the plague)
Has the dog previously lived with other dogs?
You say there are no rehoming centres - are they in the UK?

Keep separate and re home through a centre.

I think the new dog needs rehoming properly without a live in dog. They are in the UK but with the escalation being so quick and to that level the concern is about how long the wait is, especially with it being a weekend.
Otherwise she is very good, information is patchy she is old and has obviously been passed around a lot. They wanted to give her a good last home but didn't anticipate this after positive dog meets before.

I'd start getting in touch with local rescue organisations to see how quickly they might be able to help. They'll probably still have a waiting list, but prioritise a case like this over one with less pressing need for rehoming. Some also offer a home from home service, where they advertise the DDog and home check new owners but the dog doesn't go into kennels; this would at least allow the advertising process to start ASAP.

If there is a significant waiting list and the dog cannot return to its previous owner, a behaviourist would be a good option as an interim measure. We used one for a different issue and it was £150 very well spent. They may be able to spot issues the new owners haven't - for instance, if scraps have started over food, peace might be restored by feeding separately and not leaving chews etc lying around.

What breed is the DDog?

@avocadosbeforemortgages thanks for the advice regarding rehoming. She is a staffy, if found a fairly local breed specific rescue which has a form that can be filled out and contact details of other centres that may be able to help. Another concern is she needs some dental treatment, which has been booked in but would a rescue take this on?

The issue seems to be quite serious, she seems to have an issue with the dog being near the owners, guarding the owners. On her own she is a really loving, obedient dog until resident dog comes in and tries to approach the owners and she attacks. Which I think is quite a difficult behavioural issue.

It sounds like she might be resource guarding the owners - a pig, but potentially something that should be worked on if they wanted to go down that route.

That said, she sounds like my DDog who loves playing with other dogs outside the home but is less keen on me fussing the same dogs (and likes to growl when my upstairs neighbours take their DDog past the flat door, but loves the same dog in the park) and I think he'll always do best as an only dog with lots of park playmates.

You'd have to speak to the rescue about the dental treatment, but if there is insurance in place to cover it I would use that, or make an equivalent donation to relieve the strain on the charity finances.

What breed is resident dog? I'd be pretty concerned about the potential damage a dog aggressive gripping dog could do.

Fair point from @Power - was the fight very noisy or quiet?

The noisy ones tend to do little to no damage, whereas the quiet fights tend to be the most dangerous as they involve the dog clamping down.

Before anyone says it, the idea that bull breeds can lock their jaws is a myth.

Senior Staffy Club are an excellent rescue

Resident dog is a lab and not rising to it. Ran away as new dog chased and tried to attack. Poor old thing has already lost a lot of teeth at some point too.
They've been completely separated it's just a case of finding the best place for her to go now.
Her story is heartbreaking and everyone just wants the best for her because other than the dog issue shes a perfect dog.

I rehomed a large rescue who had a tragic history. It was one of those impulsive heart decisions as the dog was suffering and had little other options.
Unfortunately I already had little rescue ( with a history of abuse and lack of dog socialisation) who was not best thrilled by the new addition. In my case it was the resident dog that would attack the new larger dog. As I had taken on the responsibility I was determined to try make it work, so set up a ‘fence’ (multiple dog fences purchased off amazon) splitting the room and a baby gate for when we were out. The point of my story is that it did take a long time (6-8 months) to get to a point I was totally comfortable to leave them together. But we did get there. They are now fine. The resident dog was a) scared b) territorial/ possessive over toys & c) possessive/ jealous over us. Over time she learnt not to fear him and we trained/ told off etc re possessiveness.
It took a while for the new dog to trust her (& not be worried she would attack him). But now they play together. So these things can work out if you are able / willing to put in the time. I know someone else who had a similar problem and outcome with the addition of a second male dog.
So it doesn’t mean they will NEVER get on. Dogs like people sometimes need to learn to live together. And as one previous poster stated, dog fights look and sound terribly aggressive and frightening etc but in reality they are almost always fairly harmlesss in terms of little damage done. Dogs are usually just asserting themselves / jostling for position etc, they aren’t trying to kill each other. Though appreciate that is little solice when a fight is happening.

Personally I’d keep them apart for a while. Let the new dog settle in (she will be anxious, despite looking like she’s aggressive). Walk them together but with two people (one dog on the lead with each person). If the new dog is younger and needs more exercise give it them. Have new dog on a long lead in the living room with you. Have two baskets apart in the living room. Teach new dog to stay in her living room in the basket (on the long lead). She’s not allowed to sit right next to you and guard.. praise her every now and again. Go to your existing dog and tickle her now and again too. If the new dog reacts growl at them or say “ah” loudly and say stay. Things should eventually settle down. I’ve had this when I’ve introduced new rescue dogs occasionally, although not full on attacks. It’s always because the new dog is initially very insecure and it’s always settled down, but does take some work.

Wow, thankyou, lots of helpful advice for all angles they could possibly explore, I'm passing it all on to them.
Previous owner did get back in touch eventually and is willing to take back the dog today and wants to know when. Dog was rehomed because previous owner was out for extremely long days and she had started getting distressed with it. How do I gently say it's best if she doesn't go back there, as well meaning and caring as previous owner is I know they can not afford the dental care she desperately needs (vet quote was over £500) and I'm concerned about where she will end up. Can they say no or is this not their right?

Honestly, your friend's responsibility is to her own settled dog, not to the newcomer. Even if it is not ideal, I'm afraid they need to get the dog back to the previous owner and let their own dog live a peaceful life.

If they want to try and help remotely with finding a new home for the other dog, then good on them.