Get the water right.
The fish follow.
Free aquarium calculators and field-tested freshwater guides — written from a real working fishroom, not scraped from somewhere else.
Calculators built from real tanks.
Tank Size Calculator
Exact water volume for rectangular, bow-front and hex tanks — in both litres and gallons, with the glass-thickness deduction most calculators skip.
Open calculator → EssentialbioloadFish Stocking Calculator
How many fish your tank can actually hold — analyzing biological load capacity, surface-area oxygen exchange, and swimming-terrain preferences, with a live confidence meter.
Open → Plantedsoil · capWalstad Soil Calculator
Organic soil and sand-cap volumes for a low-tech natural setup.
Open → BreederspunnettBNS Genetics Calculator
Predict bristlenose fry morphs — albino, longfin and het carriers — from any pairing.
Open → Nano< 60 LNano Stocking Wizard
Three complete, compatible plans for tanks under 60 litres (16 US gal).
Open → No filterbowlWalstad Bowl Planner
Design a self-sustaining planted bowl — substrate, plants and safe livestock.
Open →
Most new fish die in week two. This is why.
It is almost never bad luck. It is ammonia. Cycling a tank before you add fish is the single highest-leverage thing a beginner can do — and it is genuinely simple once someone explains it without the jargon.
Everything to get started right.
Aquarium Water Parameters Explained
pH, ammonia, nitrite, nitrate, GH, KH — what each number means and what to do when it's off.
02Choosing the Right Tank Size
Every size from 5 to 125 gallons (19–470 L) — what each suits and what fish work.
03Best Fish for a 10-Gallon Tank
Nano fish, bettas, shrimp and four complete stocking combinations that actually work.
0410 Beginner Mistakes to Avoid
The predictable, avoidable errors — and how to sidestep every one of them.
05Low-Tech Planted Tank Setup
A thriving planted aquarium with no CO₂ and no expensive kit — the Walstad method, simplified.
06Aquarium Filter Types Compared
Sponge, HOB, canister and undergravel — which filter fits your setup and budget.
Written from real experience — and real mistakes.
Years of hands-on, multi-tank experience — documenting the science, the mistakes, and what actually works: an active bristlenose breeding project, low-tech planted tanks, and unheated setups that hold through extended power cuts. The photos here are all from our own tanks.
Bristlenose Pleco Breeding for Beginners
Caves, conditioning and raising fry — from a working BN project, including the albino-longfin line.
Read the guide →
The Walstad Method, Done Properly
No CO₂, no dosing — just soil, plants and a self-sustaining ecosystem that genuinely works.
Read the guide →
No-Heater Tanks: Cold-Water Species That Thrive
The freshwater fish that thrive unheated — perfect for low-energy systems and variable room temperatures, year-round.
Read the guide →Build your tank the right way.
Start with the tank size calculator — 30 seconds, and you'll know exactly what you're working with before you buy a single fish.