Cold Water Aquarium Plants UK | Coldwater Fish Tank Plants

FAQs

What are the best cold water aquarium plants for a goldfish tank?

The best cold water aquarium plants for goldfish tanks are hardy species that can withstand both cooler temperatures and the activity of goldfish. Top choices include Vallisneria, which is tough-leaved and spreads quickly; Elodea (Egeria densa), which grows fast enough to recover from grazing; Java Fern, which attaches to rocks and wood with leaves too tough for most goldfish to destroy; and Hornwort, which can be floated freely and replaced easily if grazed. All are available as cold water fish tank plants in this collection.

What temperature do cold water aquarium plants need?

Cold water tank plants in this collection are suited to aquariums kept between 15°C and 22°C — the typical temperature range of an unheated indoor aquarium in the UK. Below 15°C, the selection of suitable aquarium plants cold water species becomes very limited. Above 22°C, many cold water plants for fish tanks will still grow but may begin to show signs of stress in sustained warmer conditions. If your aquarium runs above 22°C with a heater, you should browse our main aquarium plants collection for tropical species instead.

Do cold water plants for an aquarium need CO2?

No — cold water plants for aquariums generally do not require CO2 injection. Species like Elodea, Hornwort, and Vallisneria grow rapidly in coldwater conditions using only the natural CO2 produced by your fish. A quality liquid fertiliser added weekly will support healthy growth, but pressurised CO2 is not necessary or recommended for most coldwater setups. This makes cold water aquarium plants an excellent choice for low-maintenance tanks.

Can I mix cold water plants with tropical aquarium plants?

Some species are versatile enough to grow in both cold water and tropical conditions — Java Fern and Java Moss are the most notable examples, tolerating temperatures from around 15°C up to 30°C. However, true cold water plants such as Elodea and Hornwort are not suited to sustained temperatures above 22–24°C and will deteriorate in a heated tropical aquarium. If you are unsure, check the individual product page — each plant lists its minimum and maximum temperature range.

How many cold water plants do I need for my aquarium?

A general rule is to aim for approximately 60–70% of your aquarium's surface area covered in plants when viewed from above — this creates sufficient competition against algae and provides adequate cover for fish. For a 60L goldfish tank, this typically means 8–12 individual cold water aquarium plants depending on species size. Our coldwater plant box is sized by tank volume (25L to 500L) and is the simplest way to get the right number of plants for cold water aquariums in a single order.

Cold Water Aquarium Plants — What You Need to Know Before You Buy

Cold water aquarium plants are species that thrive in unheated tanks, typically kept at room temperature between 15°C and 22°C. Unlike tropical plants that require a heater to survive, cold water plants for fish tanks are adapted to cooler conditions and often grow more vigorously in them — making them ideal for goldfish aquariums, native species tanks, and temperate freshwater setups.

The Best Cold Water Plants for Fish Tanks

Not all aquarium plants tolerate lower temperatures. The cold water tank plants in this collection have been specifically selected because they grow reliably below 22°C and are safe for the fish and shrimp typically found in coldwater setups. Key species include:

- Elodea (Egeria densa) — the most iconic cold water plant for aquariums. Fast-growing, oxygen-producing, and effective at removing excess nutrients. Can be floated or planted in substrate.

- Hornwort (Ceratophyllum demersum) — extremely tolerant of cooler temperatures and low light. Suitable as a floating plant or anchored in the tank.

- Vallisneria — a tall background plant that spreads via runners and thrives in coldwater conditions. Excellent for goldfish tanks.

- Java Fern— a versatile epiphyte that tolerates a wide temperature range, including the cooler end of most coldwater aquariums.

Are These Plants Safe for Goldfish?

Yes — all cold water plants for aquariums in this collection are safe for goldfish. Some species, such as Elodea, may be grazed by goldfish, which is natural foraging behaviour. Hardy, tougher-leafed species like Vallisneria and Java Fern are more resistant to grazing and will hold up better in a goldfish tank long-term.

Browse related collections:

aquarium plants
floating plants
potted aquarium plants
plant bundles
coldwater plant box