Aquarium treatment
Aquarium treatment covers several different products with different jobs — water conditioners that make tap water safe, medications for sick fish, and algae or water-quality treatments — and knowing which one you actually need starts with knowing what problem you're trying to solve, since they aren't interchangeable.
Water conditioners, the everyday one
A water conditioner treats tap water to remove chlorine and chloramine and neutralise heavy metals before it goes into a tank, which matters because those are added to make tap water safe for people, not fish, and can harm fish and the beneficial bacteria a tank relies on if left untreated.
This is the treatment most fishkeepers reach for regularly, every time they do a water change, rather than only when something's gone wrong — it's routine maintenance, not a fix for a specific problem.
Medications for sick fish
Fish medications are aimed at specific problems — fungal infections, parasites, fin rot and similar issues — and using the wrong one for the actual problem can be ineffective at best and harmful to fish or your tank's beneficial bacteria at worst, so identifying what's actually wrong matters before reaching for a bottle.
If you're not confident what's causing a fish's symptoms, it's worth researching carefully or asking an experienced aquarist before treating, since some medications can wipe out the beneficial bacteria that keep a tank's water quality stable, creating a second problem on top of the first.
Algae and water-quality treatments
Algae treatments and water clarifiers address a build-up problem rather than a fish-health problem directly, and they work best alongside addressing the actual cause of the algae — usually too much light, too many nutrients, or an imbalanced tank — rather than as a standalone fix.
Regular partial water changes and appropriate filtration do more for long-term water quality than any treatment added after the fact, so treatments are generally best used to correct a specific issue rather than relied on as routine maintenance in place of proper tank care.
Testing before treating
A water test kit for ammonia, nitrite, nitrate and pH tells you what's actually going on in a tank far more reliably than guessing from how the water looks or how the fish are behaving, and it's worth testing before reaching for a treatment rather than after, so you know what you're actually correcting.
Keep a basic record of test results over time if you can, since a slow drift in one reading is often easier to catch and correct early than a sudden problem that's already affecting fish by the time it's noticed.
What we stock
Everything below is in stock with us, priced with delivery worked out, and packed and posted by hand in the UK.
Large Aquarium Maintenance Set
A 48-inch condensation tray, a 22-inch glass scraper, a digital thermometer and 250ml of AquaSafe for a big tank.
£32.49
Supa Aquarium Net
Supa aquarium nets in coarse and fine meshes for fish catching and tank maintenance
From£1.65
Marina Digital Aquarium Thermometer
A digital aquarium thermometer that mounts on the outside of the glass and reads easily
£3.49
Marina Deluxe Aquarium Scraper
A four-in-one aquarium tool: two pad faces, a scraper blade and a planter fork
£8.79
Marina Floating Aquarium Thermometer
A floating aquarium thermometer with a safe-zone marker for tropical fish
£3.49
Tetra Test Strips 6in1 X10 Strips
Six-in-one aquarium test strips, results in 60 seconds, 10 to a pack
£7.74
Tetra Pond Medifin
A broad-spectrum pond fish treatment for bacterial, fungal and parasitic problems, wound-safe
From£11.34
Tetra Aquasafe
A water conditioner that neutralises chlorine and heavy metals, with an added vitamin B mix
From£6.41
Tetra Easy Balance
A freshwater aquarium treatment that Tetra say reduces how often you need a full water change, to as little as once every 3 to 6 months.
From£5.99
Aquarian Tap Water Safe
A tap water conditioner for tropical and goldfish tanks, added at water changes
£3.95
Supa Tonic Salts
A freshwater aquarium tonic salt for conditioning, outbreaks and brine shrimp hatching, 250G
£2.19
Supa Pond Blocks
Slow-release pond blocks that hold algae back rather than clearing it once it's bloomed
£3.65
Common questions
- Do I need to treat tap water before adding it to a fish tank?
- Yes, tap water generally contains chlorine or chloramine that's safe for people but harmful to fish and the beneficial bacteria in a tank. A water conditioner should be used every time you do a water change or add new water.
- How do I know which fish medication to use?
- This depends on correctly identifying the problem first, since different medications target different issues like fungal infections or parasites. If you're not confident what's wrong, research carefully or ask an experienced aquarist before treating.
- Can algae treatments harm my fish?
- Some can, particularly if used incorrectly or in a tank with sensitive fish or invertebrates, so always follow the product's instructions and consider addressing the underlying cause of the algae, such as excess light or nutrients, alongside any treatment.
- How often should I treat my aquarium water?
- Water conditioner should be used every time you add new tap water, such as during a water change, as routine practice. Medications and algae treatments, by contrast, are for specific problems rather than regular use.
Related
Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.