Your aquarium,
done properly.
Free calculators, honest guides, and a fish database — built by aquarists who made every mistake so you don’t have to.
The calculators every
aquarist actually needs.
Instant results. No account. No nonsense.
Tank Size Calculator
Get your tank’s exact volume in gallons and litres. Rectangular, bowfront, and hex tanks supported.
Fish Stocking Calculator
Find out exactly how many fish your tank can support. Uses inch-per-gallon and surface area methods with a live confidence meter.
Walstad Soil Calculator
Calculate organic soil and sand quantities for a natural planted setup. Includes Father Fish mineral layer guidance and filtration tips.
BNS Genetics Calculator
Predict bristlenose pleco offspring morphs from any parent pairing. Albino, longfin, het carriers & Punnett square — built for serious BNS breeders.
Fish Care Database
Browse care sheets for freshwater fish and invertebrates. Water parameters, temperament, diet, tank size, and compatibility at a glance.
Nano Stocking Wizard
Tell us your tank size and style — get three complete, compatible stocking plans with bioload scores, curated for tanks under 60 litres.
Walstad Bowl Planner
Design a self-sustaining planted bowl. Substrate volumes, plants, safe livestock, and a step-by-step setup checklist.
Everything you need
to get started right.
Aquarium Water
Parameters Explained
pH, ammonia, nitrite, nitrate, GH, KH. What every number means, the levels to aim for, and what to do when something looks wrong.
Choosing the Right Tank Size
Every size from 5 to 125 gallons — what each suits and what fish work.
Best Fish for a 10-Gallon Tank
Nano fish, bettas, shrimp, and four complete stocking combinations.
10 Beginner Mistakes to Avoid
The predictable, avoidable errors — and how to sidestep every one.
Low-Tech Planted Tank Setup
A thriving planted aquarium without CO₂ or expensive equipment. The Walstad method made simple.
11 min → EquipmentAquarium Filter Types Compared
Sponge, HOB, canister, and undergravel — which filter is right for your setup and budget.
Read → SpeciesBetta Fish Complete Care Guide
Everything about keeping bettas healthy. Tank size, water, feeding, tankmates, and common health issues.
Read →Real Experience. Practical Guides.
Written from 6+ years of South African freshwater fishkeeping — the mistakes, the lessons, and what actually works.
Free, honest aquarium
resources. Nothing else.
Tank Logic exists because the internet is full of conflicting advice, SEO-stuffed articles, and fish store employees who work on commission. Everything here is written to be accurate, practical, and beginner-friendly.
All tools are free with no sign-up, no paywall, and no upselling. Questions? Reach us at mytanklogic@outlook.com.
Learn more about usReady to build your tank
the right way?
Start with the tank size calculator — it takes 30 seconds and tells you everything you need to know before buying fish.