Rescue
Fish Gasping but Water Tests Fine? The Hidden Oxygen Problem
Oxygen problems are the most misdiagnosed crisis in beginner tanks. Learn the four hidden causes and how to…
Aquarium Rescue School
Stop Your Fish From Dying.
Where it hurts
What’s going wrong in your tank?
Pick the problem you’re facing and jump straight to the rescue guide.
- Fish Dying Sudden or slow losses? Find the real cause before you lose more. Fix it
- Cloudy Water Milky, green, or hazy water — diagnose it and clear it for good. Fix it
- Algae Stop the green takeover and rebalance your tank the right way. Fix it
- Plants Melting Leaves dissolving or browning? Save your plants with the right fix. Fix it
- Low Oxygen Fish gasping at the surface? Boost oxygen before it is too late. Fix it
- Toxic Water Ammonia, nitrite, chlorine — find the hidden toxins poisoning your tank. Fix it
Fresh from the lab
Latest Rescue Guides
Step-by-step fixes for the problems hurting your tank right now.
- Rescue
Why Are My Fish Dying? (When Water Tests Fine)
Ammonia zero, nitrite zero, nitrate low — and fish are still dying. Here are the real culprits most…
- Rescue
Ammonia Spike Warning Signs Most Beginners Miss
Ammonia can be lethal before your fish look obviously sick. Learn the subtle early symptoms, how to confirm…
Free tools
Aquarium Tools
Simple calculators that take the guesswork out of fishkeeping.
- Water Change Calculator Work out the exact % and volume for a safe water change.
- Stocking & Bioload Guide Check whether your tank is overstocked for its size.
- Oxygen / Aeration Check Diagnose low-oxygen risk from temperature and stocking.
- Temperature Range Finder Find the safe temperature band for your fish.
Don’t lose another fish to a problem you could have caught early.
Get the free Aquarium Survival Checklist and spot trouble before it spreads.
Tested & trusted
Recommended Gear
The essentials we recommend to keep a tank healthy. Buy once, buy right.
Water Test Kit
The single most important tool for catching toxic water early.
See our pickDechlorinator
Neutralises chlorine and chloramine before it harms fish.
See our pickAir Pump & Stone
Cheap insurance against low-oxygen emergencies.
See our pick
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