Advice for aquarium and fish tank owners

Owning a fish tank is a rewarding experience that comes with responsibilities. Whether you're cleaning your tank or parting ways with an unwanted aquarium, your actions can have a big impact on our environment. Do your part - follow safe tank practices and help protect our precious waterways.

Cleaning your tank

Regular cleaning keeps your tank healthy and your fish happy, and it's also an opportunity to protect our precious waterways.

Weekly water changes

Instead of pouring used tank water down the the sink or drain:

use it to water houseplants or your garden
discard it on grass or gravel – away from any drains.

Tank water contains nutrients that are great for plants, but may carry organisms that could harm local waterways if poured into drains.

Emptying a tank for sale or storage

If you’re packing away or selling your tank:

take it outside, away from any drains
scrub it with white vinegar and a microfibre cloth (or newspaper) to remove algae and water stains
for stubborn grime, try an algae scraper
for heavy staining, use a diluted bleach solution (1 Tbsp bleach to 4 L water) and be sure to rinse thoroughly - bleach residue is toxic to aquatic life
discard all used water on bare ground or gravel, well away from any drains.

What to do with an unwanted aquarium

Sometimes an aquarium no longer fits your lifestyle. Here are some safe, environmentally friendly options for rehoming or discarding your tank and its contents.

Dispose of aquarium plants responsibly

Aquatic plants should never be discarded into waterways. Many popular aquarium species are invasive and can harm our freshwater ecosystems.

Toss unwanted plants in your garden, well away from any drains.
Do not put them in the green waste bin in case they are an invasive species.
Pour the tank water onto your garden or on the lawn, not down any drains.
Never throw your aquatic plants into freshwaterways. Many of the plants that look great in a tank are introduced species that can cause big problems if discarded into freshwater.

Finding a new home for your pet

Rehoming is always the best option. Try these options to help find them a new home:

local Facebook groups or community forums
friends, family, or neighbours
SPCA or animal shelters
schools, rest homes, or aquarium shops
turtle rescue (for turtles).

If no suitable home can be found, consult a veterinarian for humane options. Never flush your pets down the toilet - it's cruel and harmful to the drain network.

Stop the spread of invasive species

In Aotearoa, millions of dollars are spent every year controlling pest plants that have been introduced into our waterways and waterbodies.

Don’t let your old tank become part of the problem.

Even well-meaning releases can turn pets into pests. Species like koi carp, gambusia, and red-eared slider turtles have become major threats to native wildlife.

Invasive pets can: