The new venue is the University of Hatfield where Stevie Starr, known as The Regurgitator, is transferring the fish between containers before entertaining students with the tricks of his stomach. This boy is a legend, touring the world for 11 months of the year, regurgitating for anything from pounds 3,000 (in dollars) in Los Angeles to the more humble pounds 575 (plus Vat) at the LSE.
Two shows a night and his stomach chamber is making him seriously rich. There are 90 student shows between now and Christmas when he will swallow coins, rings, fish, snooker balls - all sent down as he thumps the microphone against his chest and gives a manic laugh. His inside is also treated to butane gas, flying bees, cigarette smoke, padlocks and streams of washing-up liquid. But his constitution is, for the time being, standing up to the rigours of his calling.
'Never had a day off, never been ill. Smoke too much, eat next to nothing and spend my life swallowing coins and two cans of gas a week. Doctors can't work it out,' he says.
At the LSE, where after-hours activity was once overthrowing the government, a motley collection of students gasps as his act starts with the swallowing of a light bulb.
'Yummy,' he says, before bringing it back, quite dry. This is the hook, the swallowing made loud to prompt the gasps of disbelief. A group of Ivy League Americans, wondering what their parents are paying for, are rigid. 'Quincy, I'm going to the bathroom.'
Stevie has developed a new trick, conceived in the recent smash Australian tour, of taking an unseen pile of coins and counting them in his stomach, using, so he says, finely-tuned muscles.
But the LSE is not privy to this trick, maybe because sterling - in its present condition - is too small to identify. Stevie also declines another party-piece of selecting a specific coin inside and, like in a juke-box, lifting it out and up. Instead, he brings the money back in twos or fours, depending on audience whim, tinkling them on to the table after pummelling his chest and announcing their imminent arrival.
The BBC recorded him on the Paul Daniels Magic Show, with the producer inviting an ENT consultant from Guy's Hospital to inspect his mouth and throat. But, despite warnings given by the surgeon and Mr Daniels, the BBC thought children may copy him and dropped the item.
It made little difference to Stevie. His bookings still multiplied and the Australians, Americans and Canadians re-book him immediately, with the goldfish barely back in their bowl. The Italians go bananas about him and stop 2,000 people dancing in heaving clubs to bring him on.
He has been asked to use his talents to transport drugs, presumably to avoid the endless hours waiting in lavatories at the other end. 'Just wasn't interested,' he says. 'Told them I was happy sticking with goldfish.'
He once stunned people at an Oxford May Ball when he grabbed a moth, like a trout, and swallowed it. He thumped his chest, brought it back and let it fly away.
Impressive though this is, old-fashioned music hall knew some great regurgitators. A Frenchman, Louis Claude Delair, known perversely as MacNorton or The Human Aquarium, used to swallow 24 frogs and goldfish in a show here called Well, I Never] during the Second World War.
Non-cabaret regurgitators have also been recorded, such as Indian roadside entertainers. Scientists watched the swallowing of snakes and fish before recording them with barium meal radiography.
E A Dawes, a historian of magic at Hull University, says: 'Most of us would find it hard to overcome the gagging reflex and these manifestations remain a source of wonder - truly hard acts to swallow.'
Stevie Wright, now 29, spent the first 19 years of his life were in a Scottish children's home, near Hamilton, never knowing his family. Others, he suspects, finished up in jail or on the dole.
The story is that he began regurgitating to hide his pocket-money from bullies and went from there. 'It takes guts to swallow your first rubber ball, take it from me,' he says. 'My technique can be taught, but most people wouldn't dare do it.'
He won a local talent contest, pitched against 29 singers, and developed his act while working as a chef before a wealthy local hotel owner gave him a room. From a swallowed snooker ball it was but a short step to fish and local
So far, everything has come back on cue. But there was one memorable time when a goldfish and snooker ball got stuck in his throat and his manager had to bang him on the back, launching the ball into the audience before Stevie went for a rest after stopping breathing.
There are no such problems at Hatfield University where Stevie has already swallowed cigarette smoke, washing-up liquid and water before bringing back, yes, a bubble full of smoke. Four women students have had their rings swallowed and regurgitated, all gleaming with their internal washing.
A fat fast-food kid produces his own ring which Stevie uses for a star section: swallowing a padlock and key, bringing it all back with the ring inside the closed padlock.
The same samba muscles are used when a completed Rubik cube is tossed about inside, emerging with its sides moved. Yes, say the never-satisfied, but can he solve the puzzle inside his gut? 'Getoutovhere]'
Stevie Starr's goldfish climax is approaching. He loves students but knows that animal rights people are among them and has taken precautions. Publicity material says the act is 'RSPCA-approved', after complaints in Australia and Germany.
'Taking a live lobster and throwing it into boiling water - that's cruel, not this,' he tells us. 'They can't remember from one moment to the next.'
Teasingly, he asks if we want them back dead or alive, whole or cut up. Most of the boy students shout 'Dead]', while the girls, let it be said, plead for their safety. He drinks copious water to reduce stomach acids and they plop out, but only after one becomes stuck somewhere, so it seemed, near his pelvis.
There are no encores - counting internal change in public is still in development stage. His silver trousers and blouson are packed away, while his driver carries the fish and others aids to the waiting car.
He gives himself 10 more years on the road, if his stomach does not hoist the white flag before. Then, he says, he wants to open a grand hotel on the Italian seaside, only occasionally entertaining friends with coins and fish.