A friend who knows fish
Build your dream aquarium — and know it will work
Build your tank on screen and hear the honest why — before you buy a single fish. Shoals, water, temperaments: all checked, all explained.
Free, no sign-up needed to try the calculator.
An engine that shows its work
No black-box verdicts. Every warning explains why, cites its sources, and offers a concrete fix — from shoal sizes to predator maths built on adult mass, not the discredited inch-per-gallon rule.
Plan to scale, see the truth
Your tank is drawn in real centimetres and every fish appears at its true adult size. A fish that will outgrow your tank looks wrong before any number says so.
A curated, bilingual library
Every species is researched, sourced and quality-checked — water bands, temperament, group needs, bioload — in English and Lithuanian, with more species added every week.
How it works
Set up your tank
Pick dimensions, filtration, planting and your maintenance routine.
Add species
Shoaling fish arrive as proper groups. Everything is drawn to scale.
Read the verdict
A live health score with per-factor cards that explain and suggest fixes.
Not sure where to start?
Choose by situation
The tank you own, the water from your tap, the light that came in the box.
All 15 listsStart from a finished tank
Whole stockings, scored by the engine, opening in the planner with every fish in place.
All stocking ideasWhat a free account gets you
The calculator works without one. An account is how AquaSage remembers your water and your tanks.
Verdicts against your tap
Enter your water's pH and hardness once — from then on every species and every plan is judged against your water, not an average one.
A cycle and test log
Log ammonia, nitrite and nitrate readings — the log tells you what they mean and what to do next. You see the cycle finish instead of guessing.
A weekly reminder
The water change is the one job that can't be skipped. Turn it on once and an email nudges you until it's a habit. One click turns it off.
Your tanks, wherever you are
Plan on your phone at the shop, open it at home on your computer. Every saved tank opens back up in the planner, verdict and all.