Fishkeeping, minus the panic
Get the water right.
A dying fish is almost never a fish problem — it's a water problem, and the cause is invisible until you know what to look for. Finfern teaches the water first, in plain, kind language, with no one making you feel silly for the bowl you were sold.
Browse the care guides Free keeper tools →
No matches — try another word (e.g. a species, “cycling”, or a tool).
Every care number fact-checked against aquatic-vet & husbandry sources — never guessed. Nothing to sell you.
- 96species covered
- 22,898keeper posts analysed
- 9free tools
Start with your fish
The most beginner-friendly freshwater fish we cover — each getting a fact-checked care guide. (We cover 96 species in all, from first fish to planted-tank favourites.)
Betta
The jewel-toned solo star of the hobby — and the fish most often sold into a bowl it can't thrive in.
Nano / betta tank ✓ Care guide
Cherry Shrimp
The beginner's dwarf shrimp — colourful, a cleanup-crew helper, and prolific in stable water.
Shrimp / invert tank ✓ Care guide
Guppy
The rainbow livebearer that breeds like clockwork — cheap, colourful, and endlessly beginner-friendly (you'll soon have fry).
Tropical community tank ✓ Care guide
Corydoras Catfish
The endearing armoured bottom catfish that works in cheerful groups — a community-tank staple.
Tropical community tank ✓ Care guide
Platy
A hardy, cheerful livebearer in every colour — one of the most forgiving community fish.
Tropical community tank ✓ Care guide
Molly
A big, personable livebearer — hardy but wants harder water and more space than people expect.
Tropical community tank ✓ Care guide
Bristlenose Pleco
The manageable, algae-grazing pleco that stays a sensible size — unlike the common pleco.
Tropical community tank ✓ Care guide
Zebra Danio
The bulletproof striped starter schooler — hardy, active, and forgiving of beginner mistakes.
Tropical community tank ✓ Care guide
Fishkeeping is water-keeping
Most "my fish is sick" problems trace back to the same invisible cause — the water. The pet-store defaults (a betta in a bowl, "just add fish", a goldfish in a tank a tenth the size it needs) set people up to fail, then blame them. We teach the up-to-date, evidence-based standard — starting with the nitrogen cycle nobody explained — and we correct the myths kindly, never making you feel bad for believing them.
96 of 96 species fully sourced — every care number fact-checked before we publish it. Test, don't guess. How we fact-check →
More than care sheets
Finfern is built to answer the 2am "is this normal?" — not just with articles, but with tools that do the maths for your tank.
9 free tools
A stocking & tank-size calculator, cycling tracker, water-parameter interpreter, tankmate compatibility checker and which-fish matcher — tuned to your tank. All free, all fact-checked, nothing saved to a server.
Honest care guides
Fact-checked, plain-English guides for every species we cover — the honest minimum a fish really needs, and the myths to skip.
Guides & deep-dives
The nitrogen cycle, cloudy water, algae, water changes, disease triage — the water knowledge nobody told you, kindly explained.
A little wonder for the road
One true, cited fish fact — no pet-shop myths. Tap for another.
Did you know?
Bettas are labyrinth fishes: they gulp air at the surface and can survive in still, oxygen-poor waters like rice paddies and roadside ditches.
Join the shoal
Honest freshwater care, the occasional myth kindly busted, and new guides — straight to your inbox. No spam, no gatekeeping.
Water-first tips and new guides the moment they land. No spam — unsubscribe anytime. See how we handle your data in our privacy notice.No silly questions here. Whether you're deciding on your first fish or panicking at 2am because your tank went cloudy — welcome, tankmate. Every good tank started cloudy.