„Oh! What’s this? Are these algae? Oh no!!! Are those little animals??!!! Ahhhhh!!!!”
It sounded the same way when I discovered Hydras in my aquarium for the first time. I can calm you – Hydras are no evil monsters that want to destroy your aquarium; they are tiny (0.3mm-1cm) and very interesting animals. They are freshwater polyps belonging to the genus of cnidarians. Like corals, these little animals have tiny stinging cells on their tentacles to paralyze their prey before they eat it. They are not predators, they are very immobile and prefer to wait for their prey, which includes microorganisms such as fish larvae, small shrimp, etc.
How did they get into my aquarium?
Hydras are an indicator of good water quality – so first and foremost nothing bad. You can bring them in with plants, with animals or simply with house dust. Hydras are true survival artists.
What should I do if there is an overpopulation in my tank?
First, don’t panic. Hydras are not directly dangerous to your aquarium and are something completely natural. In most cases, they also disappear by themselves or are so little that they don’t bother. However, if they multiply explosively (for example, by over-feeding), they can still cause significant damage to your stock. To minimize the population and prevent it from spreading further, you should contact someone with a lot of experience who will get to the root of the problem and give you tips on how to counteract it. There are also fish that help with containment, or even chemicals.
A tip I got, but have not tried yet:
- Switch off the filter.
- Apply Easy Carbon (Easy Life) with a syringe (observe dosage!).
- Get close to the Hydras with the syringe and smoke them out with the Easy Carbon. Then they should be destroyed immediately.
This and other methods with chemicals you should apply only temporarily. You should find out the cause of an overpopulation to find the root of the problem. Because in the long term, chemistry harms the biological balance in your aquarium which you have been working on for so long. 😉
Thanks for reading, hope you enjoyed it. This article is written by a friend of mine aqua__craft . She has some great content on Instagram, worth a visit!