Ocellaris clownfish
Amphiprion ocellaris
Good first fish
- Care
- Beginner
- Adult size
- 11 cm
- Tank from
- 76 litres
- Temperament
- Peaceful
- Corals
- Reef safe
Photo Ritiks, CC BY-SA 3.0
Free reef tank guide for the UK and Europe
Reef keeping, step by step, with the reasons
Seafan is a free guide for new and improving reef keepers: the setup path in order, fish and coral profiles with tank sizes in litres, and plain answers where the experts disagree.
Start here
How to use this reef tank guide
A reef tank rewards patience and punishes shortcuts. Most losses in the first year come from moving too fast: adding fish before the tank has cycled, buying a fish that needs three times the tank you have, or skipping quarantine. Seafan puts the steps in order and explains why each one matters, so you can decide for yourself.
- Follow the setup path. Ten stages, each with a checklist. Tick items as you go and the depth gauge fills; your progress stays in your browser.
- Check every animal before you buy it. Each fish, coral and invertebrate page gives the tank size in litres, what it clashes with and why, and what to watch for in quarantine.
- Read where sources disagree. Brands, shops and forums give different numbers. We show the range, who says what, and our reading of why.
The pages that matter most
Pages worth reading first
- The setup path
Ten stages in order, each with a test to pass before you move on.
- Cycling, and how to prove it
Every brand's cycled claim against the ammonia test that settles it.
- Targets by brand
Every published alkalinity, calcium and nutrient target, dated, and why they differ.
- Methods compared
Eleven ways to run a reef side by side, with cost, effort and what each assumes.
- Emergency playbooks
Short numbered steps for a power cut, a hot tank, an overdose, a leak or sudden deaths.
If something is going wrong now
Emergencies: the first steps
Do these first, then open the full playbook for the reasons, recovery and prevention.
Species
Good first fish, with the reasons
Hardy, easy to feed and widely sold captive-bred, which usually means less disease risk and no fish taken from a reef. Every profile says what each fish clashes with and why.
Orchid dottyback
Pseudochromis fridmani
Good first fish
- Care
- Beginner
- Adult size
- 8 cm
- Tank from
- 114 litres
- Temperament
- Mostly peaceful
- Corals
- Reef safe
Photo Diego Delso, CC BY-SA 4.0
Banggai cardinalfish
Pterapogon kauderni
Good first fish
- Care
- Beginner
- Adult size
- 8 cm
- Tank from
- 114 litres
- Temperament
- Mostly peaceful
- Corals
- Reef safe
Photo Rickard Zerpe, CC BY 2.0
Neon goby
Elacatinus oceanops
Good first fish
- Care
- Beginner
- Adult size
- 5 cm
- Tank from
- 38 litres
- Temperament
- Peaceful
- Corals
- Reef safe
Photo Jmk7, CC BY-SA 3.0
An honest note on sources
Who we learn from
We learn from BRS TV, Red Sea, Triton, Tropic Marin, Reef Builders, Practical Fishkeeping, UK shops and many keepers. Seafan is independent and not affiliated with any of them: we write everything in our own words, say who said what, and link to their pages so you can read them yourself.
Every page lists its sources with the date we read them. Figures we saw only in a search summary are marked typical, check. If you spot a mistake, email products@cameronshields.co.uk.
Read how we choose and check sources
Species profiles last checked . How we check
Questions about Seafan
Is Seafan free?
Yes. Seafan is a free guide with no paid tier, no adverts and no affiliate links. It is a trading name of Cameron Shields Ltd.
Is Seafan linked to BRS, Red Sea or Triton?
No. We read and link to their guides, manuals and videos, but Seafan is independent and has no affiliation with any brand, shop or forum.
Why are tank sizes in litres?
Most care sheets give US gallons, which are smaller than UK gallons. We give litres first, with UK and US gallons on request, so 100 US gallons (379 litres) is never mistaken for 100 UK gallons (455 litres).
What does "typical, check" mean?
It marks a figure we found only in a search summary, not on a page we read in full. Treat it as a typical value and check it before you rely on it.
How do I report a mistake?
Email products@cameronshields.co.uk with the page and what you think is wrong, with a source if you have one. We check every report and correct the page with a new date.