UK guide

Reef keeping in the UK: costs, buying, medicines and the law

Most reef guides are written in the US, in US gallons, dollars and Fahrenheit, for US shops and US law. This page collects what is different for a keeper in Great Britain, with a source and a date for each point.

Last checked 21 October 2026. How we check

How much does a reef tank cost to run in the UK?

Electricity is the biggest running cost. Ofgem’s price cap for 1 October to 31 December 2026 is 26.32p per kWh for electricity, with a standing charge of 54.83p a day, and VAT on electricity is removed from 1 October 2026 to 31 March 2027 (Ofgem notice, read as a search summary: check the notice for your region and payment type).

That is about £31.33 a month, or about £376 a year, before salt, RO/DI filters, test kits and food. Your own figures will differ: a plug-in energy meter on each device gives the real number. Heaters run far more in winter and in a cold room. Practical Fishkeeping’s electricity article worked at the old 34p cap, so its totals are now too high.

Keepers on UK forums report all-in monthly costs of about £50 for a 175 litre tank (about £25 to £30 of power, £10 to £15 of salt, £3 of water) and about £150 for 500 litres (typical, check). Starter RO/DI units sell for about £80 to £200 (typical, check). Livestock prices are on each fish profile.

How do I size a heater for a UK home, and survive a heatwave?

Many UK homes cool down at night and when the heating is off. UK and EU retailers size heaters by room temperature: about 1 watt per litre in a heated room of about 19 C, 1.5 W per litre at 15 to 18 C, and up to 2.5 W per litre at 13 to 14 C (typical, check). Split the total across two heaters, each on its own controller, so one stuck on cannot cook the tank.

In a heatwave, a fan blowing across the water surface cools by about 2 to 3 C (Reef Builders). Reef Builders also suggests lights on later and for less time, and keeping blinds closed (search summary). A chiller is hard to justify for a few hot weeks a year in most UK homes (Reef Builders and UK forums, search summary). See tank too hot and power cut.

Can I use UK tap water?

Not for a reef. UK tap water is often treated with chlorine or chloramine and can carry phosphate and silicate (our reading; we found no national list of which water companies use chloramine). Your water company publishes a water quality report for your postcode. RO/DI water is the default for mixing salt and topping off, and BRS says top-off water should read 0 TDS. Some aquatic shops sell RO water if you do not want a unit at home.

Where do UK keepers buy livestock and equipment?

We do not recommend shops by name, and Seafan has no affiliate links. The main kinds of seller are:

• Local aquatic shops with a marine section. You can see the fish eat before buying, and ask whether they quarantine.
• Specialist online marine retailers that deliver livestock by courier. Check their dead-on-arrival terms before you order.
• UK coral farms and frag sellers selling tank-grown corals. A US farm that sells its own corals says tank-grown pieces settle most easily, though the source is not neutral.
• Other keepers and clubs selling or swapping home-grown frags. These never cross a border, so CITES permits do not arise, but dip and quarantine them like any other coral.

How is livestock delivered in the UK?

Royal Mail will not carry fish or hard corals, and couriers carrying live fish need transport authorisation from the Animal and Plant Health Agency (OATA, read as a search summary). Someone has to be in to receive the box. Have water ready, at the right temperature and salinity, before the courier arrives, and photograph any losses on arrival for the seller’s dead-on-arrival claim.

Which fish medicines can I buy in the UK?

This is the area where US advice fits the UK least. UK keepers report that copper treatments are sold by UK aquatic retailers, and that some drugs named in US quarantine guides, such as metronidazole, need a vet’s prescription here (forum reports, typical, check).

What are the rules on importing corals (CITES)?

• All stony corals, plus black, blue, organ pipe and fire corals, have been on CITES Appendix II since the mid-1980s. Soft corals, zoanthids, mushrooms and anemones are not listed (Cefas).
• In Great Britain these corals need an import permit from the Animal and Plant Health Agency, checked by Border Force on arrival (GOV.UK, Cefas).
• Live animals are not covered by the personal-luggage exemption, so you cannot bring stony corals home from holiday or order them directly from an overseas seller without permits (GOV.UK).
• Moving CITES specimens without a valid permit can bring up to 7 years in prison, an unlimited fine or both (GOV.UK).
• Great Britain keeps its own list of import suspensions, last replaced on 5 October 2026. Since January 2023 it has included most corals from Queensland, Australia. Northern Ireland follows the EU list (GOV.UK).
• A UK aquatic dealer received a suspended sentence for smuggling 136 CITES-listed corals, and OATA advises asking a seller for the import permit number (Practical Fishkeeping).

In practice, UK keepers buy imported stony corals from licensed importers and shops, and frags grown in UK tanks trade freely between keepers (our reading).

Do I need a licence to sell frags?

OATA says every business selling fish commercially needs a licence from its local council. In England, the 2018 animal licensing regulations cover selling animals as pets; whether a hobbyist selling spare frags counts as a business depends on tests such as making a profit, and the councils’ guidance we saw was summary only (typical, check). If you sell regularly, ask your council.

Can I release or dump unwanted livestock?

No. Releasing non-native animals into the wild is an offence under section 14 of the Wildlife and Countryside Act 1981 (read as a search summary). Rehome through a shop, club or another keeper instead.

UK gallons or US gallons?

A UK gallon is 4.546 litres; a US gallon is 3.785 litres. Most care sheets use US gallons without saying so, so a fish needing 100 gallons needs 379 litres, not 455. Rules such as one snail per gallon need the same care. Seafan gives litres first, with UK and US gallons labelled. See the glossary for other units.

Home insurance rarely covers livestock or losses from equipment failure; check your policy (our reading).