Tetra Bactozym, 10 capsules is a bacterial culture conditioner for aquariums from the German brand Tetra. It stimulates biological activity: organic colloids coat the filter media and all surfaces with an invisible film on which beneficial filter bacteria thrive. The improved formula contains highly active enzymes and bacterial spores. According to the manufacturer, the first fish can be added just 24 hours after setting up a new tank. It suits freshwater and marine aquariums, at 1 capsule per 100 L of water.
Why an aquarium needs bacteria
Fish excrete ammonia, and leftover food and plant matter decompose. Ammonia and the nitrites formed from it are toxic to fish. Nitrifying bacteria in the filter and substrate turn them into less harmful nitrates, which are removed with water changes. A new tank has few of these bacteria, and without help the colony takes several weeks to form. More on setting up in aquarium for beginners: what to buy.
Key specs
| Parameter | Value |
|---|---|
| Type | bacterial culture conditioner |
| Components | enzymes, bacterial spores, organic colloids |
| Aquarium type | freshwater and marine |
| Dosage | 1 capsule per 100 L |
| Adding fish | after 24 hours |
| Quantity | 10 capsules |
| Brand | Tetra, Germany |
Pros
- Quick start-up. Fish can go in after 24 hours.
- Protects the biofilter. During water changes and media replacement.
- After medication. Restores weakened bacteria.
- Enzymes. Help break down organic waste.
- Freshwater and marine tanks.
- Capsules. Easy to dose.
Cons
- One capsule per 100 L. Awkward to dose for small tanks.
- Doesn't replace water testing. You still need ammonia and nitrite tests.
- Stock gradually. Too many fish at once risks poisoning.
- 10 capsules. Enough for a few treatments in a large tank.
How to use it at start-up
Fill the tank, treat tap water with a dechlorinator, then install and switch on the filter. Add capsules at 1 per 100 L: open the capsule and tip the contents into the water near the filter. After 24 hours you can add the first fish — just a few, with the rest introduced gradually over several weeks. Feed sparingly at first.
During water changes and filter maintenance
A big water change, rinsing or replacing filter media reduces the bacteria. The manufacturer says Bactozym helps prevent a significant drop in their activity. Add it after such maintenance, and rinse filter sponges in tank water rather than tap water to preserve the colony.
After treating fish
Many fish medicines suppress beneficial bacteria. After a course of treatment, do a water change and add Bactozym — the manufacturer notes that it restores microorganisms harmed by medication. Meanwhile, watch your fish's behaviour and water parameters.
How to tell the tank is ready
Water tests are the most reliable way. While ammonia and nitrites are above zero, don't add more fish. Signs of trouble include rapid breathing at the surface, lethargy and clamped fins. If you see them, change some water and cut back on feeding. More in how to feed aquarium fish.
Storage
Store the capsules in their closed pack somewhere cool and dry, out of sunlight and away from children and pets. Don't add the product at the same time as fish medication — the bacteria will die; wait until the course is over and you've changed the water.
Alternatives
For starting a new tank there are also liquid bacteria such as Rikka Aqua Start, and for stabilising water Rikka Aqua Balance. All products are in the fish medicines and water care section.
Verdict
Tetra Bactozym is a capsule product with enzymes and bacterial spores that speeds up starting a new aquarium and helps preserve the biofilter after water changes, media replacement and fish medication. Dosing is easy at 1 capsule per 100 L. The downsides are that small tanks need the capsule split, and water testing is still essential.
FAQ
What's the dosage?
1 capsule per 100 L of water.
When can fish be added?
After 24 hours, according to the manufacturer, but gradually.
Is it suitable for a marine tank?
Yes, for freshwater and marine aquariums.
Should I use it after treating fish?
Yes, it helps restore bacteria after medication.
Can I use it when replacing filter media?
Yes, to keep bacteria active.
How many capsules are in a pack?
10.
Do I need water tests?
Yes, they show whether the tank is ready for fish.
