Listen to the Song – A Home Inside a Shell
The complete lyrics are included in the companion book, Our Jewels in the Water, allowing readers to follow every song while learning about Britain’s remarkable freshwater fish.
Enjoying the music?
The companion book Our Jewels in the Water includes the full lyrics, additional stories, exclusive photographs and beautiful illustrations for every species.
The Bitterling
A Home Inside a Shell
“Hidden among the plants of quiet waters lives a tiny jewel with one of the most remarkable partnerships in the freshwater world.”
Species Profile
The Bitterling (Rhodeus amarus) is a small, beautifully coloured freshwater fish with an extraordinary way of reproducing.
Its story is inseparably linked with freshwater mussels. Rather than simply laying her eggs among plants or gravel, the female Bitterling uses a long tube called an ovipositor to place her eggs inside a living freshwater mussel.
There, protected within the mussel’s gill cavity, the developing young are given a remarkably safe nursery.
This unusual relationship has made the Bitterling one of the most fascinating small fish found in British waters.
Clive’s Story
Small fish have always fascinated me because they reveal an entirely different world beneath the surface.
As youngsters, many of us began our interest in fish not with rods and reels, but with a little net, a jam jar or a bucket beside the water. Every tiny creature we discovered seemed important.
The Bitterling represents that same sense of discovery.
At first glance it may appear to be simply another small silver fish, but learn about its life and suddenly an extraordinary story unfolds — a fish whose future depends upon another freshwater creature.
That is exactly what Our Jewels in the Water is about: looking beyond size and discovering the remarkable stories hidden beneath the surface.
Natural History
Bitterling favour slow-moving or still waters such as ponds, lakes, canals and gently flowing rivers where aquatic vegetation and freshwater mussels are present.
They feed on small invertebrates, algae and other tiny food particles.
During the breeding season the male can develop beautiful colours, while the female develops her distinctive ovipositor.
She uses this slender tube to deposit her eggs inside a suitable freshwater mussel. The male then releases sperm close to the mussel’s inhalant opening, allowing fertilisation to take place inside.
The developing young remain protected within the mussel until they are sufficiently developed to emerge into the surrounding water.
The relationship goes even further. Freshwater mussel larvae can temporarily attach themselves to fish, which helps the mussels disperse to new areas.
It is one of freshwater nature’s most remarkable partnerships.
Interesting Facts
- Scientific name: Rhodeus amarus
- Common name: Bitterling
- Family: Acheilognathidae
- Average size: Usually around 5–8 cm
- Habitat: Slow rivers, canals, ponds and lakes with aquatic vegetation
- Diet: Algae, plant material and small invertebrates
- Special feature: Females lay their eggs inside living freshwater mussels
- Breeding: Males become particularly colourful during the breeding season
- Distribution: Found in parts of Britain and widely across continental Europe
Behind the Song
When writing A Home Inside a Shell, I wanted the song to tell more than the story of a tiny fish.
The relationship between the Bitterling and the freshwater mussel seemed almost made for a song.
One creature provides shelter for another, allowing new life to develop safely inside its shell. In return, fish can also play a part in the mussel’s own life cycle.
It is a wonderful example of how closely connected life beneath the water can be.
The song celebrates that hidden partnership — and reminds us that sometimes the greatest stories in nature belong to its smallest creatures.
Conservation
The future of the Bitterling is closely connected to the health of the waters in which it lives — and particularly to the survival of freshwater mussels.
Pollution, habitat degradation, excessive sediment and the loss of aquatic vegetation can all damage the delicate environments upon which these species depend.
Protecting healthy ponds, canals, lakes and rivers therefore protects much more than one species.
It protects an entire community of interconnected freshwater life.
Clive’s Reflection
The Bitterling reminds me why we should never judge the importance of a fish by its size.
Here is a tiny creature that could easily pass unnoticed, yet its life contains one of the most extraordinary stories in freshwater nature.
A fish and a mussel — two completely different creatures whose lives become connected beneath the surface.
That is why I think A Home Inside a Shell is such an appropriate title.
The shell isn’t simply somewhere to hide.
For the next generation of Bitterling, it becomes their first home.
Small in size, yet full of wonder — another true jewel in our waters.