About AquaKeepers

Yes — AquaKeepers is completely free. There are no paid tiers or feature limits.

AquaKeepers supports both freshwater and saltwater aquariums. Each type is pre-configured with default parameters and equipment.

Yes. Add as many aquariums as you like — each has its own parameters, health score, and event history.

The health score is calculated from your logged parameter readings, how recently you measured, and how long it’s been since your last water change. Readings outside the configured range reduce the score.

Yes. AquaKeepers is a web app that works well on phones and tablets. Open it in your mobile browser at app.aquakeepers.com.

Go to app.aquakeepers.com and create a free account. No credit card required.

Forget the old “one inch of fish per gallon” rule — fish mass grows with the cube of length, and the rule ignores behaviour and territory entirely. Think in adult size, waste output, and species behaviour instead, and add fish a few at a time, weeks apart. Our stocking guide walks through it.

About 25% weekly is the gold standard for a typical community tank (10–30% depending on stocking). Small and regular beats large and occasional. See the maintenance routine.

Almost certainly “new tank syndrome”: the tank wasn’t cycled, so invisible ammonia poisoned the fish. A new tank needs 3–6 weeks to grow the bacteria that neutralise fish waste — before any fish go in. The nitrogen cycle section explains how to do it right (and how to know when you’re ready).

For tropical fish, yes to both. The heater keeps water at a stable 24–27 °C (about 1 watt per litre). The filter isn’t optional cleaning equipment — it houses the bacteria that convert toxic fish waste, and without it the tank can’t support life for long. Details in equipment, explained.

Yes — once treated with a water conditioner (dechlorinator), which neutralises the chlorine and chloramine that would otherwise harm fish and kill filter bacteria. Never add untreated tap water to a running tank.

In a new tank, a milky haze a few days in is a bacterial bloom — completely normal, clears on its own, and chemicals only prolong it. In an established tank, persistent cloudiness usually points to overfeeding or an overdue water change.

Healthy adult fish are fine up to a week without food — for a weekend, do nothing at all. For longer trips, use an automatic feeder (test it for a week first). Don’t feed extra before leaving; uneaten food becomes ammonia. More in feeding without polluting.

A solid freshwater setup runs roughly €140–380 (tank, filter, heater, light, substrate, test kit) — fish and plants come gradually after cycling. Saltwater starts at 3–5× that. Full breakdown in planning your first tank.