Have you ever walked by your freshwater tank only to notice tiny spots floating by? These stringy creatures are the tentacled monster many aquarists dread known as Hydras.
In this post, I’ll talk about what they are and how you can get rid of them. I’ll also answer a few common questions, like ‘do Mollies eat Hydras?’
Let’s dive in.
Do Mollies Eat Hydra?
Yes! Mollies are one of the handful of fish species fond of eating Hydra. Luckily, they’re large enough not to be affected by the Hydra’s stinging tentacles.
They’re also easy to care for and maintain, making them the perfect addition to your Hydra-infested tank.
Molly fish are mainly carnivores; they’ll eat anything! They’ll gobble up anything in sight without a fuss.
Yet, they prefer grazing on plant and algae growth in the tank. If there are no algae, you can feed them spirulina flakes and store-bought Mollie food. You can also offer some chopped-up pieces of boiled spinach.
So, add some Mollies to your tank and watch them eat away those pesky Hydras!
What Are The Challenges Of Keeping Mollies To Get Rid Of Hydra?
Molly fish are small-sized tropical fish known for their hardiness and ability to adapt to a wide range of water conditions.
However, this usually results in aquarists making the mistake of not managing tank conditions as closely as they should. It’s actually one of the biggest challenges of keeping mollies to get rid of Hydra.
When this happens, it becomes like a domino effect, where one problem leads to another. For starters, a disturbance in water conditions leads to bacterial or fungal infections, such as fin and tail rot, swollen gills, and red blood spots.
Other challenges include:
- Bad water quality
- An unclean tank
- Overfeeding your fish
- Adding tank mates that are incompatible with mollies, like goldfish
- Leaving toxins to accumulate by overstocking the aquarium or not cleaning it regularly
- Introducing new plants and aquatic decor to the tank before disinfecting them
- Leaving leftover foods, decayed plants, and dead fish in the tank, even for a day
- Being impatient and rushing the tank’s nitrogen cycle
- Failure to closely monitor water temperatures, as well as oxygen and pH levels
How Long Does It Take For Mollies To Eat All Hydra In The Tank?
Hydras are virtually unnoticeable members of the same genus as corals, the Phylum Cnidaria, and the class Hydrozoa.
This is one of the oldest animal groups in the history of evolution, which they share with jellyfish, corals, and myxozoans.
These small, soft-bodied freshwater polyps look like skinny corals and can be off-white, brown, or green.
The Hydra population often starts small. Nevertheless, their ability to regenerate means that one hydra can quickly become hundreds in a matter of days.
That said, the reason why adding molly fish to the tank to get rid of hydra is one of the best and most effective! For one, mollies are easy-going and low-maintenance, as long as you provide them with ideal tank conditions.
The other reason is that mollies snack on Hydras, their eggs, and whatever food the Hydras prey on.
Therefore, estimating how long it would take for mollies to eat all the Hydra in the tank depends on a few factors. First, you have to consider the size of the tank. Then, there’s the amount of Hydra, as well as the number of mollies in the tank.
Let’s start with what you can control: the number of mollies.
It’s recommended that a 10-gallon tank is ideal for one molly. Yet, keep in mind that mollies are schooling fish, which means they don’t like being alone.
Subsequently, to keep them healthy and happy, you should keep at least three to four mollies per tank; three females and one male.
That said, you have to remember that each extra mollie needs an additional five or more gallons of aquarium space.
I also have to mention that using a chemical like ‘No Planaria’ can get rid of Hydra in one hour after an initial dose. So then, over the following few days, the second and third doses are just precautionary measures.
Yet, some aquarists prefer not to add chemicals to their tanks for fear of disrupting the pH levels or harming other fish.
Consequently, they look for safer alternatives, like adding Hydra-eating mollies to the tank.
So, considering all that, our best estimate of how long mollies will take to finish off the Hydra population in your tank is about a week at most.
Afterward, make sure you follow the proper preventative measures, like overall maintenance of the tank and everything in it. Regular cleaning is also an important step in preventing and eliminating Hydra from your aquarium.
Other Ways To Get Rid Of Hydra In Aquarium (Without Using Mollies)
Even though Hydras are virtually unnoticeable, there are still multiple ways you can get rid of them. Check out these methods that can help remove Hydras from your tank once and for all without using mollies
Yet, before I get into that, I should advise you against removing Hydras manually from the tank. You risk breaking off a piece, which will regenerate into more Hydras and make the problem worse.
Instead, try one of these ideas:
- Reduce the amount of food going into the aquarium, forcing them to starve to death
- Target feed your fish to prevent excess food from floating and spreading in the tank
- Carry out a 25% water change every 1 – 3 weeks, depending on the size of the tank
- Stir and vacuum the gravel routinely to get rid of leftover food
- Treat plants and decor in hydrogen peroxide or a bleach solution before introducing them to the tank
- Use a chemical agent, but there’s a risk it can be toxic to other tank inhabitants
- Remove fish and plants, then raise tank temperatures to 105℉ – 110℉ for several hours
Other Fish Species that Eat Hydra
Hydras are pretty good at finding the perfect hiding spot. Like snails, they stow away in various places until they get to a place with shelter and good food.
One way they do that is by sneaking into your freshwater tank along with water from a fish bag. It’s also possible that they hitch a ride on aquatic plants, driftwood, and rocks.
You can always get rid of Hydras the old-fashioned way: by adding more predators. Besides Mollies, almost any type of carnivorous or omnivorous fish will gladly munch away at these tiny polyps, as long as they’re small enough to actually notice the Hydra.
Snails are always happy to prey on Hydra. Plus, they’re too slow to go after shrimp or baby fish, so they’re not considered a threat.
Not only that, but snails do a terrific job of cleaning up any foods leftover from the fry, which makes them the perfect addition to any freshwater aquarium.
If the fish don’t seem that interested in eating the Hydra, you can try reducing the number of feedings. This will help whet their appetites and make the Hydra seem more appetizing.
In addition to Mollies, here are a few other fish types that typically feed on Hydras:
- Betta fish
- Paradise fish
So, do Mollies eat Hydra? Yes, they do!
Bringing these two unique water creatures together is like a match made in heaven. Mollies can help reduce the Hydra population, eating even their eggs and prey, which means no more nasty little Hydras hanging around in your tank.
That said, it’s essential to know other ways to eliminate these pesky species, like disinfecting aquatic plants and knowing which fish species are also fond of eating Hydras like mollies.
It’s true that there’s no way of completely preventing Hydra from popping up in your tank. However, it’s worth taking all the necessary precautions to help limit their numbers as much as you can.
It’ll save you a lot of hassle in the future!
Hi! I’m Praveen Ghoshal, the founder of eFishkeeping.com. Inspired by my Dad, I got interested in fishkeeping when I was a kid. Since then, I have been involved with this hobby. Currently, I have 3 fish tanks at our home, where I enjoy this hobby with my Mom, Dad, and Younger Sister. Read more about me here.