Working with fish is not for the squeamish. For a start, you might be required to perform a Section 30. In a former goat-feed store converted into a laboratory by FE students during their introduction to the aquatics course at Brooksby Melton College, lecturer, technician and course tutor Richard Pearson prepares to demonstrates the procedure.

Using a scalpel and surgical tweezers, he removes the eye from a dead roach, then removes the lens, cuts it open and dollops the resulting goo on a glass slide.

He peers through a microscope and prods the sample until he finds what he is looking for. “There,” he announces, pointing at a translucent worm still wriggling in the goo. “Diplostomum spathaceum. It’s a parasite, and it lives in the eye of a fish, right inside the lens.”

The life cycle of Diplostomum spathaceum is a thing of wonder. As an adult, it lives in the intestines of a fish-eating bird and enters rivers and lakes by way of the bird’s droppings. There, its offspring penetrates the body of a freshwater snail, which in turn is eaten by fish. Diplostomum spathaceum enters the lens of its new host, causing cloudiness and impaired vision explains Mr Pearson, “and because the fish can’t see too well, a bird can easily catch it and the cycle begins over again”.

Although ingenious, this organism is also a nuisance for anyone involved in fish husbandry. Which is why checking for its presence - 30 individuals must be dissected each time a population of fish is moved from one body of water to another, hence the term Section 30 - is one of the many skills required of employees in the burgeoning aquatics industry.

And in terms of sheer up-close-and-dirty experience, there is probably no better place in the country to acquire such skills than here in the fisheries department at Brooksby Melton College.

Once the country seat of 1st Earl Beatty, commander of the British fleet at the Battle of Jutland, this former agricultural college 15 miles north-east of Leicester has provided fish-related courses for 13 years. And demand for places is growing all the time.

One reason is that the scope for employment for someone with the right qualifications is enormous, says Mr Pearson. He is a former painter and decorator who came to Brooksby to do a national diploma and ended up staying as a lecturer. Several of his former students now have jobs with the Environment Agency; others manage lakes and rivers where people pay to fish. Or they work in fish-farms, restocking fisheries that service the ornamental trade or the dining table.

And thanks to the growing interest in keeping tropical fish in the home - and celebrities prepared to splash out tens of thousands of pounds for a single koi carp - there is any amount of work to be found in sales and marketing.

“One student came to us from Scotland,” Mr Pearson recalls. “Now he has his own shop in Thailand, selling tropical fish. And he learned it all here.”

“Here” has changed since Earl Beatty’s time: the panelled state rooms now provide office and conference space and the Gothic chapel does a brisk trade in weekend weddings. But the ornamental lakes are maintained with the care that the sea lord would have expected, providing endless training opportunities for the students.

However, much of their tuition is done in a collection of brick and concrete sheds by the River Wreake. In their dark temperature-controlled tanks are freshwater species of every description. Each is there for a specific reason, whether to teach students how to build a working filtration system from scratch or replicate typical living conditions in an Asian river, or how to light a tank in a way that best displays the iridescent beauty of its inhabitants.

Together with a series of large ponds on the far side of the estate, the gurgling facilities in these buildings mirror those at a commercial fish farm to provide students with experience of managing stock, draining and sterilising lakes, netting and transporting mature fish and manipulating every stage of spawning, hatching and nurturing.

“Everything you see here is built, maintained and worked by the students,”

says Mr Pearson. “They do the brickwork, the woodwork and the plumbing. A lot of colleges are now getting into fish because it’s a growing industry and people are realising that they need trained, professional staff. But we don’t try to compete. We offer what we offer, which is hands-on real stuff.”

Which is not to say that the work does not have its more aspirational side.

In partnership with the Environment Agency, Brooksby students are involved in a unique project that could reintroduce a species that became extinct in British waters 30 years ago.

Through a door at the far end of one shed, Mr Pearson leads the way into a gloomy chamber filled with mysterious tanks, whose occupants remain hidden in sections of plastic pipe. They are burbot, imported from Denmark, where they still survive in the wild.

While these freshwater cod might lack the obvious appeal of many of the species at the school - the Siamese fighting fish or a pair of extraordinary mud skippers, which spend much of their time in the open air, for example - their presence has already made headlines in the local press.

Mr Pearson explains: “If we can get burbot to breed at the current temperature of the River Wreake, that would disprove the theory that global warming caused them to die out here.”

It will be several years before the project is complete and the team know whether it is safe to release burbot into streams and rivers. But Mr Pearson is not about to lose interest. “The more you look into fish, the more amazing they are,” he says. “I have been mad about them ever since my mother caught me hand-feeding the family goldfish at the age of five.”

Making his way back to his office, past the piranha, the sea ponies and the two mud skippers, who sit goggle-eyed on a log waiting for someone to toss them a grasshopper, he stops to feed his favourite fish, George, a huge, red-tailed catfish whose tank was built by the students after George outgrew his home in a local aquarium shop.

“With certain species of catfish,” he says, quickly moving his hand out of range to avoid a nip from the giant, “you can get them to spawn by raising the temperature of the pond for a while and then sprinkling cold water on the surface.

“They think it’s the rainy season, which is when the rivers swell and flood into the plains, filling them with shallow warm water where zooplankton thrives -the plankton that the fry will live on.”

You half expect him to add Michael Caine’s famous line, “Not a lot of people know that”.

But why would he do that? After all, it’s a situation he’s working hard to rectify.