How to move your koi and goldfish safely.

House prices continue to rise at an incredible rate and the competition for the next rung on the property ladder is so fierce that many are sold as soon as they are advertised. Consequently, the housing market has never been as buoyant with many homeowners looking to trade up to bigger and better houses. All well and good, but what if you have a pond full of fish that you want to take with you?

A house move demands organisation at every level. Furniture can be packed by professionals, fragile items wrapped with care, and pets transported with relative ease — but moving pond fish is a specialist task that should never be left to a removal company. Whether you keep goldfish, shubunkins or koi, relocating pond fish requires careful planning to minimise stress, prevent water quality problems and reduce the risk of disease after the move.

Every move is different, but the key to safely transporting pond fish lies in preparation, controlled transportation and careful acclimatisation at the new location.

Understanding Stress When Moving Pond Fish

Fish are highly sensitive to environmental change. Sudden shifts in water quality, temperature, oxygen levels and handling all trigger stress responses. Importantly, disease outbreaks often occur days after the stressful event rather than immediately. During a house move, fish may experience repeated netting, temporary confinement and fluctuating water conditions. These factors weaken immunity and increase susceptibility to bacterial infections and parasites.

The objective when moving pond fish is therefore simple: reduce stress at every stage.

Preparation Before Moving Pond Fish

Ideally, fish are moved during cooler weather. At lower temperatures, fish metabolism slows, they are less active and produce less waste. This reduces ammonia build-up in transport water. Unfortunately, completion dates are dictated by solicitors rather than fish biology, so you must adapt best practice to your schedule.

Reduce feeding in the days leading up to the move, particularly during warm weather. Fish can comfortably go without food for up to a week. An empty digestive tract means less waste during transport, helping preserve water quality inside bags or tanks.

Collect clean pond water for transport before you begin netting. Disturbing the pond bottom stirs up sediment and debris, which should not be used for transport. Clear, pre-collected pond water offers better conditions for the journey.

Professional fisheries use large aerated fibreglass tanks for transporting fish, but most household moves rely on heavy-duty polythene fish bags secured with elastic bands. These are widely available from aquatic retailers.

Recruit help. Netting and bagging fish is far easier — and less stressful for the fish — when carried out calmly by two people. Fish should be guided gently into a net rather than chased. Prolonged pursuit increases respiration rates and raises oxygen demand inside the transport bag.

Transportation: Minimising Risk During the Journey

A floating cage net placed in the pond before bagging can simplify the process. Fish can be gently transferred into the cage and then bagged swiftly once everything is ready.

Where possible, inflate transport bags with oxygen rather than air. Ideally, around 80 percent of the bag volume should be oxygen, with 20 percent water and fish. Double-bagging reduces the risk of leaks. Place the sealed bags inside boxes or dark bin liners to reduce light exposure, which helps calm fish during transport.

Keep transport time as short as possible. Even though imported fish may spend many hours in bags, that does not mean it is stress-free. Elevated respiration and excretion rapidly degrade water quality in confined conditions.

Common Hazards When Moving Pond Fish

Physical injury during netting is a major risk. Spooked fish may collide with pond walls or pipework, leading to scale loss or bruising that can later develop into ulcers. Always guide fish head-on into a net rather than chasing from behind. Vigorous chasing can also cause fish to leap from the pond.

Water quality deterioration inside transport bags is another hazard. Stress increases ammonia production and oxygen consumption. Minimising bag time and maintaining adequate oxygen are critical for safe transport.

Acclimatising Fish to Their New Pond

In most house moves, the new pond will not be biologically mature on moving day. A newly filled pond requires several weeks for beneficial bacteria to colonise the filter system. This means temporary accommodation is often necessary.

Options include negotiating short-term access to your old pond after completion (if practical), boarding fish with a trusted pond-keeping friend, or setting up a temporary pond and filter at your new property.

To avoid New Pond Syndrome, stock the new pond gradually. Even if all the fish belong to you, adding them all at once to an immature system risks dangerous ammonia and nitrite spikes.

An effective way to accelerate filter maturation is to transfer mature filter media from your existing pond. This seeds the new filter with established beneficial bacteria and significantly shortens the biological stabilisation period.

When introducing fish to a new or temporary pond, float the sealed bag on the surface for around five minutes to equalise temperature. Then open the bag, roll down the top and gradually add pond water to mix water chemistry before release.

Water testing is essential during this period. Nitrite is particularly important, as it is toxic and often persists longer than ammonia in immature systems. Only add additional fish when nitrite consistently reads zero.

Preventing Jumping After a Move

Newly introduced fish often attempt to jump during their first few days in unfamiliar surroundings. Cover the pond securely with netting to prevent losses. This is especially important for active species such as Orfe.

Observe fish closely for several weeks after the move. Watch for reduced appetite, lethargy, clamped fins or visible abrasions. Address any water quality issues promptly and treat injuries early to prevent secondary infections.

Moving Pond Fish: A Simple 7-Step Plan

1. Decide on transport method — oxygenated bags or a suitable tank.

2. Arrange destination — mature pond, friend’s pond or temporary filtered system.

3. Reduce feeding and collect clean pond water.

4. Net fish calmly with assistance and bag securely.

5. Float and acclimatise fish properly at their destination.

6. Monitor water quality daily, especially nitrite levels.

7. Cover the pond and inspect fish regularly for signs of stress or injury.

Moving pond fish is undoubtedly one of the most demanding parts of a house move, but with careful preparation, controlled transport and gradual acclimatisation, it can be completed safely. The key principles are simple: minimise stress, protect water quality and never rush the biological maturity of the new system.