The free AqAdvisor alternative for freshwater tanks
AqAdvisor pioneered the online aquarium stocking calculator, and a lot of us still have it bookmarked. But the interface is dated, it leans on ads, and its compatibility warnings are thin. App-aquatic's stocking calculator is a modern, free alternative: it estimates bioload from your real tank, filtration and planting, then checks every pair of fish and tells you the reason for each clash and how to fix it. No sign-up, no ads.
Runs the same engine as the App-aquatic app. Works on your phone. Share any setup with a single link.
AqAdvisor vs App-aquatic, side by side
| Feature | AqAdvisor | App-aquatic |
|---|---|---|
| Price | Free, ad-supported | Free, no ads, no sign-up |
| Bioload / stocking estimate | Yes | Yes, modern less-conservative engine |
| Pairwise compatibility with a reason and a fix | Basic warnings only | Yes - full matrix, reason + fix per clash |
| pH and temperature overlap check | Partial | Yes |
| Biotope / origin matching | No | Yes |
| Planted-tank adjustment | Basic | Yes, plus recommended plants |
| Recommended tanks and setups | No | Yes |
| Linked species care guides | No | 763 guides |
| Shareable setup link | No | Yes |
| Mobile-friendly interface | Dated | Modern, responsive |
| Companion mobile app | No | iOS & Android |
| Freshwater | Yes | Yes |
| Saltwater / marine | Yes | Freshwater focus |
AqAdvisor is a long-running, genuinely useful free tool, and it still covers marine tanks, which we do not. If you keep a freshwater or planted community, the comparison above is where App-aquatic pulls ahead.
Why people switch from AqAdvisor
You get the reason, not just a red flag. Most calculators tell you two fish "may not be compatible" and stop. App-aquatic checks every pair for temperament, predation, fin-nipping, adult size and overlapping pH and temperature, then shows the specific reason and a concrete fix - add a sight-line barrier, raise the group size, swap to a deeper tank, and so on.
The bioload model is less conservative, and explains itself. Older calculators often flag a perfectly sensible community as overstocked. App-aquatic credits filtration turnover and planting, applies a lighter penalty to low-waste species like neons and rasboras, and now names your single limiting factor - biological waste, filtration or swimming space - so you know exactly what to change.
It is part of a full app, not a dead-end page. Every species in the calculator links to a full care guide, and the same engine lives in the free App-aquatic app for iOS and Android, where it travels to the fish store with you.
How the modern bioload model differs from "1 inch per gallon"
The classic rules - one inch of fish per US gallon, or one centimetre per litre - are easy to remember and almost always wrong. They ignore filtration, planting, waste output and the fact that a 10 cm goldfish produces far more waste than 10 cm of neon tetras. AqAdvisor improved on this with a bioload estimate, and App-aquatic takes it further by modelling filtration turnover, plant uptake and per-species waste, then showing you the old inch-per-gallon and cm-per-litre numbers side by side for context. You can see all three the moment you add fish to the stocking calculator. We ran the numbers on this ourselves: 71% of the most popular beginner fish need more than a 10-gallon tank once you actually run the bioload math.
AqAdvisor alternative FAQ
What is the best free alternative to AqAdvisor?
App-aquatic's stocking calculator is a modern, free AqAdvisor alternative. It estimates bioload from your tank volume, filtration and planting, and adds a full pairwise fish-compatibility matrix that gives a plain-English reason and a suggested fix for every clash - with no sign-up and no ads.
Why does this calculator show different numbers than AqAdvisor?
Both tools estimate bioload, but they weight filtration, planting and waste output differently. App-aquatic mirrors the App-aquatic app's engine, applies a lighter penalty to low-waste species and credits planting and filtration turnover, so sensible communities read as balanced rather than overstocked.
Is App-aquatic's stocking calculator really free?
Yes. It is completely free, needs no account or login, and shows no ads. You can plan as many tanks as you like in the browser and share a setup with a single link.
Does it cover saltwater like AqAdvisor?
App-aquatic focuses on freshwater and planted aquariums, with 763 freshwater species care guides. AqAdvisor also covers marine. If you keep a freshwater community, App-aquatic gives more detailed compatibility, biotope and planted-tank guidance.
What does App-aquatic add over AqAdvisor?
A pairwise compatibility matrix with a reason and a fix for every clash, pH and temperature overlap checks, biotope and origin matching, planted-tank adjustments, recommended plants and tanks, links to 763 species care guides, a shareable link for each setup, and a companion iOS and Android app - on a modern, mobile-friendly interface.
Try it now
Plan your tank in the browser - no account, no ads, no waiting.