Keeping Temperate Fish and Shrimp in the UK
With energy bills still running high, more and more fishkeepers in the UK are looking for ways to enjoy the hobby without the cost of running a heater around the clock. One of the best ways to do that is by setting up an unheated — or "temperate" — aquarium. The good news is that there's a whole range of fascinating fish and shrimp that will thrive in a tank kept at room temperature, provided your home is heated and you set things up properly.
Why Maturity Matters: Set Up Your Tank Before You Stock It
This is the single most important point in the whole guide: every aquarium must be fully matured before any fish are added — and this is especially true for shrimp.
A mature tank means the nitrogen cycle is up and running, with established colonies of beneficial bacteria converting harmful ammonia (from fish waste) into nitrite and then into much less harmful nitrate. Without these bacteria in place, ammonia and nitrite can quickly build up to lethal levels — and shrimp are far more sensitive to water quality than most fish. Even small spikes that a hardy fish might shrug off can wipe out a whole colony of shrimp overnight.
So before you add anything living to your tank:
Set it up with your substrate, filter, decorations and plants.
Run the filter and let the tank cycle, which typically takes several weeks.
Test your water regularly until ammonia and nitrite both read zero and you're seeing low levels of nitrate.
Only once the tank is stable and mature should you introduce your first stock.
Patience here pays off enormously. A rushed, immature tank is the number one cause of losses in temperate setups, and shrimp are usually the first to suffer. Mature the tank first, every time.
Where to Position Your Tank
Because an unheated tank depends on room temperature, where you place it really matters. You want to avoid anything that causes the temperature to swing up and down:
Keep it away from draughts, open windows and exterior doors.
Avoid placing it near radiators, fireplaces or other heat sources.
Keep it out of direct sunlight, which can overheat the water and encourage algae.
Put it somewhere quiet, away from loud noises, vibrations and sudden movements — fish stress easily in chaotic environments.
Use overhead tank lighting to maintain a consistent day-night cycle, which helps keep your fish healthy and settled.
Stability is the goal. The less the temperature fluctuates, the happier and healthier your fish and shrimp will be.
A Note on Temperature
Even though these are temperate species, tank temperature should never be allowed to drop below 17°C. If your home runs cold, or you're keeping the tank in a room that might fall below that during winter, you should use a heater to keep the temperature stable and within the safe range for whatever species you're keeping. Unheated doesn't mean uncontrolled — it just means you're relying on a warm room rather than a heater most of the time.
Fish and Shrimp That Thrive in Unheated Aquariums
If your home is heated and your tank is mature and stable, there's a lovely variety of species that will do well without a heater:
Zebra and leopard danios — active, hardy little shoalers
Rosy and golden barbs — colourful and lively
White cloud mountain minnows — peaceful and undemanding
Variatus platys — bright and easy to keep
Bronze and peppered Corydoras — charming bottom-dwellers that love to shoal
Hillstream and weather loaches — fascinating character fish
Amano and cherry shrimp — excellent cleanup crew and captivating to watch
One important restriction: while these species are suitable for indoor unheated aquariums, they are not legally permitted to be kept outdoors for biosecurity reasons. They must only be kept in indoor aquaria. So no outdoor ponds for these — indoor tanks only.
The Takeaway
Temperate fishkeeping is a rewarding, lower-cost way to enjoy the hobby — but it's not a shortcut that lets you skip the fundamentals. Position your tank thoughtfully, keep the temperature stable, choose the right species, and above all mature your aquarium fully before adding any fish or shrimp. Get those basics right, and an unheated tank can be just as vibrant and fascinating as any heated setup.
Happy fishkeeping!
Read our stocking calculator and our 3 step guides to setting up and aquarium and setting up a shrimp tank :