• The MasterChef Australia recap collection: we watch the show so you don't have to
• ​How Saint Peter chef Josh Niland is changing seafood cookery

It seems like Sunday elimination night has given Jock a case of the gloom. As the contestants walk into the kitchen, he's feeling all sentimental about how much they have given up to be here: Emelia, you put your business on hold to come back; Callum, you left your newborn baby to prove you can win; Laura, you stopped cooking pasta at your pasta restaurant to cook pasta on MasterChef, good for you I love pasta don't stop ever.

Andy is standing in front of an ominous shape hidden by a sheet. DON'T WORRY, it is not a dead body but rows of different types of fish.

Andy reveals that there will be a special guest judge tonight, a fish legend. He's won best restaurant of the year, best chef of the year, a few hats, but most impressive of all, he went to school with Andy. What an honour!!! It's Saint Peter chef and – as the MasterChef Twitter account put it oh-so-cringingly earlier today – the "so-fish-ticated" fish butcher extraordinaire, Josh Niland.

The contestants gasp. Tessa says she is a huge fan. Laura admits to scrolling 72 weeks-deep on Josh's Instagram account.

Josh Niland is all about using every part of the fish. He jokes that his fish eyeball prawn cracker is possibly too crazy for the upperclass Paddo crowd (they only eat shark eyeballs, thank you very much) at his restaurant, but he always tries to minimise what goes in the bin. Hopefully he will still throw Andy in the bin today with some embarrassing high school gossip.

The first round will be "Name That Fish", which Andy thinks sounds like a gameshow… a really, really boring one. Each contestant has to take it in turns to guess a type of fish and whoever gets it wrong goes into round two.

Josh puts his butchering gloves on and Simon looks like he's about to go for his yearly colonoscopy. He guesses flathead, and guesses right. Next is Callum, who correctly chooses pink snapper. When it comes to Khanh's turn, he is worried because the only fish names he knows are ones with pretty colours in the title.

He starts having visions: he thinks he sees a salmon, but maybe it's not a salmon!? Is that a Murray cod or is it Bill Murray? He thinks he can see yellow fins on a big tuna in the back so guesses it's yellowfin tuna. Wrong.

The guessing game continues until Emelia, who admits to Josh that her fish knowledge is as limited as her on-screen personality, incorrectly guesses a kingfish and joins Khanh in the loser's line.

Reece is next, whimpering like a scared puppy. He likens the experience to a trip to the aquarium without all the helpful plaques. Also without all the dead fish, you'd hope. He picks the smallest fish and guesses it's a sand whiting. Nope.

Laura was too busy checking Josh's Instagram feed that she wasn't listening to what just happened and guesses the same little fish Reece picked was also a sand whiting! Proof that social media melts our brains.

Tracy is next and incorrectly guesses Murray cod. She joins Khanh, Emelia, Reece and Laura in the bottom round cooking a kingfish. Josh flexes his butchering skills and starts taking apart the fish bit by bit. He scales the fish, which he says he uses on his fish-fat caramel slice at Saint Peter. He cracks the head off and says he needs to "negotiate the organs out". Look, he seems like a great guy and all, but this also sounds like something a serial killer would say.

Jock asks, "how cool is this?" and everyone agrees that it is, indeed, very cool. Khanh says it's "outrageously awesome", Emelia says her mind is blown when she sees Josh cut a fish-tail shank, Poh says she would rather watch Josh break down a fish snout to tail than "go to the opera". I don't think going to the opera is really very high on anyone's scale of "cool things to do", but look I guess I get what she means.

They draw a number out of a hat to choose who picks first. Khanh gets number one, and picks the round darne cutlet. Emelia chooses the four-point rack. Tracy chooses the double cutlets, which someone says looks like the devil, I'm looking at Emelia The Strange. Reece chooses the belly and Laura gets what she was hoping for, the tail chop. I wonder if Josh is a bit disappointed that none of them chose more challenging cuts like the shank or fish collars or head? So boring!

They have 60 minutes to cook, which Josh says is a long time to cook fish so he expects creativity. Emelia and Khanh run to the pantry and say they might vomit. I don't think this is what Josh means when he says to be creative.

Emelia goes one step further and tells the gantry "she's soiling herself". Someone get Emelia a prescription of antibiotics! But she says she's just nervous because this is her first elimination cook, simultaneously humble bragging about never being in an elimination before.

She is making a cioppino seafood stew with roasted kingfish on top. We get a bit of Emelia's backstory, which involves her standing around telling some mystery people how to ice a cake in true emotionless Emelia style. She says she has spent the last few years working on her cake business so this fish challenge really puts her out of her comfort zone. Fish-fat caramel slice, I repeat, fish-fat caramel slice!

Tracy is chopping pork belly and chorizo - she's going to pan-fry the fish in Spanish flavours. Andy says the flavours are huge and hopes they won't outshine the fish. Tracy says she wants "lush mouthfeel", which doesn't sound all that great to be honest.

Reece, the vegan pastry chef, has decided to cook chicken in this fish challenge. Don't worry, I'm just as confused as you. He says he is doing something classically French, and chicken and fish go really well together. I'll just take his word for it.

Laura tells us she has lots of great memories going to the beach, "catching fish, foraging for succulents", which sounds like maybe she had a deprived, possibly survivalist childhood.

Josh and Andy come out to see what Laura is foraging in the herb garden: samphire, warrigal greens and purslane. She tells Josh she's making a smoked pipi creme fraiche emulsion with succulents and wakame oil. Josh thinks it is fancy. Laura's like, "oh stop it, Josh (don't stop)."

Khanh has decided to tempt fate – he plans on cooking the same dish that got him eliminated in season 10: his Vietnamese sweet and sour soup, canh chua ca. So many things went wrong in that last cook – he left things off, he burnt his fish – and we get a flashback to a red-eyed baby Khanh getting yelled at by Shannon Bennett.

Last time Khanh says he was trying to be too cool by pan-frying the fish (again, really questioning the contestants' idea of what "cool" is), when the traditional way is to poach the fish in the broth on the bone. Khanh is feeling all Russell Crowe in Gladiator, he wants redemption.

Reece is sticking to the "cool" way to cook fish – pan-frying – but isn't confident, so puts it in the oven to make sure it cooks through. If this isn't a producer's trick to foreshadow imminent overcooking, then I haven't been watching MasterChef for the past eight weeks straight (I have).

Laura wants to cook her tail chop on the hibachi, because it's been a few days since someone mentioned the hibachi, but thinks there is too much meat on her chop, so starts hacking off half of it. Jock grills her on why she wasted half the fish that Josh had butchered so perfectly and looks mad. Laura starts panicking that he won't give her preferential treatment anymore.

Emelia says her cioppino sauce is too salty, so tries to bring it back by adding water and butter. She pan-fries the fish rack skin-side down and then finishes it in the oven. She doesn't want the fish to be overcooked, but judging by her faded backstory earlier, $100 says it will be.

Khanh's test piece is perfect, but he realises it is going to be overcooked by the time it's served. Jock reminds him the fish can't be "squeaky", so Khanh decides to cook the second piece at a lower temperature, just like his mum would tell him to.

Tracy's cutlet is really thin so she has to be careful she doesn't overcook it. She takes it out of the pan several times, prodding the cutlet meat like she's giving it a Swedish massage. Her fingers all over those cutlets are giving me major COVID-19 alarm bells. Where are your gloves, Tracy!!?

Emelia is making a seafood wreath bed for her fish. She has no idea if her rack is cooked or not, which sounds not ideal.

At two minutes to go, Khanh is freaking out because he thinks his fish is still raw. He needs it to get up to 45 degrees. Jocks thinks history might be repeating himself, which shows you how much faith Jock has in Khanh.

Everyone starts plating up, so Khanh puts his damn darne on the plate anyway and just sends out a prayer.

Laura is first one up to the judges' table with her kingfish tail chop surrounded by smoked pipis and succulents. Andy tries to bait Josh by saying he "noticed it was smaller than what Josh cut." But Josh thinks it looks great and doesn't seem to care that she wasted half the fish and that's what he's always going on about. Laura says she is frustrated because she wears the elimination black apron more than the white apron. Just a hunch, but maybe don't cook pasta every dish, Laura!

Josh says he is really impressed with the skin, and we know how he loves crispy fish skin. Andy loves it, he thinks it was cooked perfectly. Josh agrees and hopes his chefs at Saint Peter can replicate it at the restaurant, which is maybe a burn to his chefs? Melissa says the smoky pipi sauce was a genius move. Jock says she nailed it but wishes she used the whole piece. Sorry, daddy!

Reece is up next with his crispy skin kingfish belly with vegetables and chicken stock. He says this was a challenge for him and Melissa says "You can't cook cake everyday" and A, why not, and B, what about Laura and her daily pasta?

Jock says it looks like every fish dish in London in the early 2000s, and pretends he means this as a compliment. Andy is nodding his head like he knows what Jock means and wasn't just an electrician from Maitland in the early 2000s.

Josh cuts it up; it's very overdone. Andy says the sauce had "a bit of flavour", which tells us nothing. Melissa can't really think of anything nice to say about the taste, so just says it looks "a riot of spring-summer".

Emelia is next and hopes she's cooked her fish properly. Andy says Emelia doesn't give much away about how she really feels. Don't we know it. She says she's terrified because she is used to making cakes and this is way out of her comfort zone. Josh says she should be proud because it looks great.

It doesn't taste great though. He cuts into it and it looks as well-done as my cat's Fancy Feast. Melissa says it is "undeniably, overwhelmingly overcooked", which is maybe as mean as Melissa gets. She also says the sauce is too salty. Josh says the pipis were "a nice gesture", which I think is the critic equivalent of "it's the thought that counts".

Tracy puts down her kingfish cutlets with chorizo sauce and charred sweetcorn. She says the double cutlet reminded her of a bull and that's why she was inspired to cook Spanish flavours. Jock asks her how she feels being back and she says she feels good. In her first season she was always doubting herself, but this time she feels like she is just proving her ability.

Any hopes of that are dashed though as Josh cuts into it. Melissa looks like that emoji baring all its teeth, only with red lipstick. Josh says on a scale of one to 10 in overcookedness, it's 11/10. Melissa looks like she wants to spit it out. Andy says at least the corn was cooked nicely. Jock uses one of his favourite burns: "it was so well-done it could pat his own back". Melissa says it was a confused cook and it did not come together cohesively. See ya Tracy, we barely knew ye.

Meanwhile Khanh arrives with his canh chua ca Vietnamese soup and supposedly raw cutlet. He says he could have gone with an easier dish, but it's one of his favourites and he was so sad it didn't get him through last time. Josh cuts into the fish just in time for a suspenseful ad break!!

Back in the kitchen, Josh says "pearly translucency", which sounds like something he might have learnt from Andy. But thankfully it means it's perfect. Josh likes it so much he drinks his soup from the bowl like someone from the wrong side of Paddington.

Josh says it was incredible and he is so happy to finally be served some fish that was cooked well. How embarrassing that three out of five contestants decimated his fish! Andy says it's a cracker, because it's been a few days.

So now we have to get down to business, and obviously Laura and Khanh are safe.

Reece, Emelia and Tracy all overcooked their fish. Tracy's also looked bad, so she's out. Tracy says "it's all good" about a million times before realising it's not all good and then bursting into tears. She says it has been a great experience and she has learnt a lot as a person. Off she pops back to the Barossa, where takeaway food apparently doesn't exist, but at least she can drown her sorrows on some great bold reds.

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