Moving fish tank: how to move an aquarium without losing fish

To move a fish tank safely, take the fish out, keep the filter media wet in tank water, drain the tank completely, and move it empty. The two things that kill fish after a move are a dried-out filter (which loses its helpful bacteria) and a tank that leaks because it was carried with water or gravel inside.

Plan the move so the tank is set up again the same day if you possibly can. Fish in bags or buckets are fine for several hours, and the filter bacteria survive a day or so if kept wet, but every extra hour adds risk.

How to identify it

Which kind of move is this? The plan is different.

Across the room or to another room: a short move. You still need to drain most of the water, but the fish can wait in a bucket for an hour or two.
To a new house nearby (under about 2 hours): the standard move in this guide.
A long drive (several hours or overnight): needs insulated containers, battery air pumps and planning for temperature. See the long drive section below.

Water weighs about 1 kg per litre (8.3 lb per US gallon). A 200-litre (55-gallon) tank holds roughly 200 kg (440 lb) of water, plus the weight of glass, rock and gravel. Never try to move a tank with water in it.

When it's a problem

Normal after a move: fish hiding, pale and off their food for a day or two; slightly cloudy water for a few days.

Watch closely: ammonia or nitrite showing on a test in the first two weeks. The filter bacteria took a hit and need time.

Emergency: fish gasping, a leak at a seam, or the heater left running in a dry tank. Unplug equipment and see fish gasping for air or cracked or leaking tank.

What you need

Fish bags (ask your fish shop) and rubber bands, or clean food-safe buckets with tight lids. Never use buckets that have held soap or chemicals.
An insulated cooler or polystyrene box to hold bags and keep the temperature steady.
A battery-powered air pump with airline and airstones for buckets and the filter media.
Clean containers with lids for filter media, plants and some tank water.
A siphon or pump and hose for draining.
Towels and blankets for padding the tank.
Water conditioner, a test kit, a thermometer for the other end.
A helper. Glass tanks are awkward and slippery even when empty.

Step by step

Before moving day

Do a water change 2–3 days before, so the fish start in clean water.
Stop feeding 24–48 hours before the move. Hungry fish produce less waste in the bags. Healthy adult fish manage this easily.
Prepare the new spot: a level, strong stand, near a power outlet, away from radiators, sunny windows and doors.
Check your new tap water. A different town may have different pH, hardness or chloramine. Test it, and use conditioner that removes chloramine.

On moving day

Unplug the heater first, at least 15 minutes before you drain, so it cools down. A hot heater out of water can crack.
Save tank water. Fill bags or lidded buckets with water from the tank for the fish, the filter media and plants.
Catch the fish. It's easiest after removing decor and lowering the water. Use two nets: one to herd, one to catch.
Bag the fish. Fill bags about one-third with tank water and two-thirds with air. Professional shippers use pure oxygen; if your fish shop offers to fill bags with oxygen, accept. Put territorial or spiny fish in separate bags. Plecos and catfish with spines can puncture bags, so double-bag them or use a bucket.
Keep the filter alive. Put the sponges and media into a lidded container, fully covered with tank water. For moves over a few hours, run an airstone in it from a battery pump. Don't rinse media in tap water.
Plants: put them in bags with a little tank water, or wrap them in wet newspaper.
Drain the tank fully and remove all gravel, sand, rock and decor. Gravel can stay damp in a bucket; this keeps some bacteria alive too. Even a small amount of gravel in a moving tank can strain the seams.
Move the tank empty, padded with blankets, upright, never carried by the top rim.
Keep the fish container in the car, not the trunk or a moving truck, out of the sun, and keep the room or vehicle at a comfortable temperature.

Setting it up again

Place the empty tank on its stand and check it is level.
Add the substrate, rock and decor, then the saved tank water, then fresh dechlorinated water at the same temperature.
Put the filter media back and start the filter as soon as there is enough water.
Wait 15 minutes after filling before plugging in the heater, so it adjusts to the water temperature.
Acclimate the fish by floating the bags for 15–20 minutes, then adding small amounts of tank water over another 20–30 minutes before netting them in. See acclimation.
Lights off for the rest of the day.

The next two weeks

Don't feed on the first day. Then feed lightly, about half the usual amount, for a week.
Test ammonia and nitrite every day or two. If either shows above zero, change 25–50% of the water. This is a "mini-cycle"; see cycling and ammonia.
Don't add new fish for at least a month.

On a long drive

Pack bags upright in a cooler or polystyrene box with the lid on. Darkness keeps fish calm.
Check the temperature every few hours. Tropical fish ship best at about 26–30°C (79–86°F). In cold weather use heat packs wrapped in newspaper, never touching the bags; in hot weather a wrapped cold pack. Avoid fast swings: about 1°C (2°F) per hour is the most you want.
Large fish do better in a lidded bucket with a battery air pump.
Don't feed during the trip.
If the trip is overnight, open the bags at the hotel and add fresh oxygen by squeezing the air out and re-inflating, or move fish to a bucket with an air pump.
For very long or international moves, consider rehoming fish to a trusted keeper or shop and restarting, or ask a fish shop to pack them with oxygen.

Common mistakes

Moving a tank with water or gravel still in it. This twists the frame and can cause leaks days later.
Letting the filter media dry out or rinsing it in tap water.
Leaving fish in a cold car or a hot moving truck.
Adding a full bag of fish to a tank of brand-new, untreated tap water.
Feeding normally straight after the move, when the filter is weakened.
Forgetting to unplug the heater before draining.

Products that help

Battery air pump: keeps fish buckets and filter media oxygenated during the move.
Insulated cooler or polystyrene fish box: holds temperature steady.
Heavy fish bags and rubber bands: safer than loose containers for small fish.
Lidded food-grade buckets: for large fish, media and water.
Water conditioner that handles chloramine: for the new home's tap water.
Bottled nitrifying bacteria: may help top up the filter after a move; results vary.
Liquid test kit: for daily checks after setup.

Why it matters

Most of the bacteria that turn fish waste into safer compounds live on the filter media and gravel. In a brand-new tank they take six to eight weeks to build up. If they dry out or die during a move, ammonia can rise within days, just when the fish are already stressed.

When to get help

Ask your local fish shop to bag your fish with oxygen for a long trip; many will. Get help if fish are gasping after the move, or ammonia or nitrite stays high for more than a week despite water changes.

In the game

Multiple Tank Syndrome doesn't have a moving day card yet.