Quick answer
Fish in the UK typically cost £2–£200. PetTrader lists fish from licensed breeders, private sellers and rescues, across 6 breed guides, with prices, locations and health details on every advert. Listings follow Lucy's Law and the Animal Welfare (Licensing of Activities Involving Animals) Regulations 2018.
Fish typically sell for £2–£200 in the UK. Price depends on breed, species or variety, health testing and registration paperwork, the seller's location and the time of year. Anything priced well below the range below is worth questioning — it is a common sign of an unlicensed seller or a scam advert.
| Specie | Typical UK price |
|---|---|
| Koi Carp fry | £20–£500 |
| Goldfish fry | £3–£40 |
| Betta Fish fry | £8–£60 |
| Guppy fry | £2–£15 |
| Discus Fish juveniles | £30–£150 |
| Cichlids juveniles | £5–£60 |
Run the tank with a source of ammonia for four to six weeks until ammonia and nitrite both read zero and nitrate is present. A liquid test kit is essential — test strips are not accurate enough. This one step prevents most beginner losses.
Common plecos reach 45cm, silver sharks 35cm and goldfish 20cm or more. Aquatic shops sell them small, so check the adult size and the shoal size each species needs before adding it to your list.
Where possible quarantine new fish for two weeks in a separate tank so illness does not spread. When adding them, float the bag to match temperature, then drip acclimatise over 30–45 minutes, and net the fish across rather than adding shop water to your tank.
Most aquarium fish cost £2–£200. Community tropicals such as tetras, guppies and corydoras are a few pounds each, bettas and cichlids £10–£40, and marine fish and quality koi run into the hundreds. The tank, filter and heater are the main outlay.
Yes. A new tank needs four to six weeks of fishless cycling so the filter grows the bacteria that convert ammonia to nitrite and then nitrate. Adding fish to an uncycled tank is the single most common reason beginners lose them.
Stocking depends on adult size, waste output and swimming style rather than a simple inch-per-litre rule. Research the adult size of every species before you buy — common plecos, silver sharks and goldfish all outgrow the tanks they are usually sold for.
For a tropical community, guppies, platies, danios, corydoras and neon or ember tetras are hardy and inexpensive. For coldwater, white cloud mountain minnows suit smaller tanks; goldfish need far more space than most people expect.
Keep the bag dark and insulated, get home quickly, then float the sealed bag in the tank for 15–20 minutes to match temperature before drip-acclimatising to the water chemistry. Net the fish into the tank rather than pouring in transport water.
Small pond goldfish and shubunkins are a few pounds each, standard koi £20–£100, and Japanese-bred show-quality koi many hundreds. Any pond fish needs proper filtration, depth for winter and protection from herons.
View the animal in person at the seller's own home before any money changes hands, keep all messages inside PetTrader so there is a record, and never pay by bank transfer, gift card or crypto to someone you have not met. Every PetTrader seller completes a photo-ID and live selfie check, and verified accounts carry a badge, and you can report an advert from the listing page.
Selling rather than buying? Identity-verified private sellers get their first advert free, and the first 200 businesses and breeders get 12 months free. Read where to advertise fish for sale in the UK for the options, costs and legal rules, or how to rehome a pet if you are finding a new home for one you already own.
