Changelog — what shipped

Two new guides — betta tank mates by tank size (engine-computed, including the honest "none" for small tanks) and how many fish fit in your aquarium — plus a tap-water match tool: enter your pH/GH/KH, see which species thrive in your water untreated.

Curated rule: betta × gourami pairings now warn — they are close anabantoid relatives and males often treat each other as rivals. Previously the engine could score these green.

Tank-mates guides for 30 popular species — every companion scored by the engine, with the specific reason behind every warning.

Metric ↔ US units toggle in the header — °F, inches and gallons everywhere, remembered on your device and account.

"Help us improve" button — ideas, bugs and species-data corrections land straight on the founder's desk. We read every message.

The planner is now a proper workbench: named panels, a Clear-tank button, and an aquascape that actually shows your planting and hardscape in the tank.

Pair compatibility heatmap in the verdict — tap any two species to see exactly why they got their verdict.

Advanced tank setup: filtration turnover, surface agitation, substrate, lid and CO2 now feed the verdict — and travel inside shared plan links.

The methodology page — every formula, threshold and limitation of the engine, in the open. Plus five utility calculators under /tools.

Species pages answer the questions people actually ask — tank size, water, group size — in both metric and US units.

Engine v0.1.1: curated safe-pair rules now silence the predation gate too, exactly as documented.