Hydra in Your Aquarium? Here's How to Handle It!

Have you ever spotted those tiny tentacled creatures stuck to your plants or the glass in your aquarium? They might be Hydra!

Bewildered and kind of scared? Don't worry, you're not alone.

While they might look like something out of a sci-fi flick, eradicating them is totally doable.

What is Hydra, Anyway?

Imagine a miniature version of a sea anemone, about as big as a grain of rice.

Hydra are freshwater creatures related to jellyfish, corals, and sea anemones. Growing up to 0.4 inches (1 cm), they range in color from translucent white to green to light brown.

Hydra anchor themselves to surfaces in your tank with a stalk and wave around long, stinging tentacles to catch their prey.

Fun fact: they're also kinda immortal—cut one up, and you'll get a bunch more.

How Did They Get in My Tank?

Hydra can sneak in on plants, decorations, or even live foods you've added.

They lay low until conditions are just right (like when you start feeding baby brine shrimp a lot), and then bam—population explosion.

Are They Dangerous?

Hydra are natural inhabitants of almost all freshwater environments in the world. Chances are, they're in your tank now.

To us big humans, they're harmless. Their stingers are too weak to bother us.

But for tiny tank residents like baby shrimp or fish fry, those stings can spell trouble. Keep an eye out if you've got vulnerable little ones in your tank.

They have indeed been seen stinging and snagging the tiniest baby fish and shrimplets, so if you plan to breed the tank seriously, this is something to watch for.

Are They Bad for My Tank?

They're more annoying than harmful.

Hydra snack on tiny organic stuff that floats past. Think: debris, microworms, and other microscopic animals in the water column.

They will snag a baby shrimplet if they can, but they won't wipe out your whole tank. Adults and bigger fish are usually safe from their attacks.

How Do You Get Rid of Hydra?

One effective solution we personally use is 'No Planaria', a powdered Betel nut additive that completely wipes these guys out. It kills off most invertebrates in the tank.

Just a heads-up—it's not snail-friendly, so relocate any shelled friends before treating your tank. We put them back after a few months of weekly water changes.

Follow the package instructions as to dosage!

If bombing the whole tank isn't your style, opt for a more natural (albeit longer) approach:

Reduce feeding—especially live foods—and keep your tank clean to starve them out. Filter the heck out of your water, and up the vacuuming.

Introduce micro- predatory fish like rasboras, guppies, or danios—they’ll happily munch on hydra without a second thought, and keep numbers negligable.

My Hydra Takedown Story

This April, in my Snowball shrimp breeder tank, I faced a full-on hydra invasion.

With no fish to keep them in check, my baby shrimp were at risk.

After relocating the snails, I treated the tank with a scoop of that powdered 'No Planaria', let it sit for a week, then did frequent water changes to clear out the leftovers.

I added back in my nerites and mystery snails, but noticed the Malaysian trumpets and ramshorns I had in there actually did just fine. Some random Planaria I had seen were gone too. No plants were affected at all.

It took some patience, but eventually, my shrimp were safe and hydra-free.

So, there you have it—your guide to kicking out hydra. Stay vigilant, keep it clean, and your tank will stay hydra-free.