Adding Freshwater Invertebrates to Your Tank

First Things First

Chances are pretty high that at some point in time you have considered added invertebrates to your home aquarium. And why not? There are so many to choose from, and many will provide useful services for your tank. If you have ever been to a specialty pet store, or shopped around online, you know that invertebrates come in all different shapes, sizes, and colors. I can't tell you how hard it was to convince my boyfriend that the pretty blue freshwater crawfish would not be a good fit for our aquarium. All he knew was that they looked calm and peaceful in the tank, not to mention they were a brilliant shade of blue.

This is the kind of thing a lot of pet stores hope for actually. They want to lure you in with bright colored fish and invertebrates in hopes that you will indulge in an impulse buy while you are there. However, you are smart people and you know that you should never add anything to your tank without first doing the proper research. Though, sometimes you can't help but add a fish or two to your purchase when they look particularly healthy and are often not in stock.

Back to the topic of invertebrates. There are five type of invertebrates that are common in freshwater aquariums: shrimps, snails, crayfish, clams, and crabs. There are many different species within each category, each one having a different temperament.

Snail tank used to house snails in effort to create a self populating culture
Snail tank used to house snails in effort to create a self populating culture


Freshwater snails are some of the most common invertebrates in home aquarium systems. They come in a variety of sizes, ranging from pea sized to the giant apple snail. Most snails will happily eat the algae in your tank and not bother the other inhabitants. However, if you have live plants in your aquarium you might have a bit of a problem.

First, chances are high that if you bought your plants at the pet store and they were housed in water that you already have snails present in your tank. This is because snails will feed upon live plants. Adding more, or larger, snails to your tank could mean the death of your live plants.

Snails are hermaphrodites, this means that they can reproduce as both a male and a female. If your tank has an excess of food your snails will feed and then reproduce very quickly. Snails lay eggs, lots of eggs. If you don't want hundreds of baby snails in your tank you can try getting rid of them, but you will most likely not be very successful if there are a lot of places where the snail is able to lay its eggs that you can't reach. For this reason I would recommend only have one snail, or if you want more than one getting different species.

Some fish eat snails. If you are buying the snail to be a pet you will want to make sure that none of the fish in your tank are known fish eaters. However, snails are great for feeding snail eating fish: loaches, freshwater puffers, betas, and gouramis. If you are going to be using live snails to feed you fish you still need to be careful of them reproducing. Ideally your snails will reproduce and you will have a self populating food source. My recommendation would be to keep only a few snails in your main tank and the rest in a smaller tank. As your fish eat the snails simply replace them with snails from your snail tank. Hopefully the snails in the smaller tank will reproduce to keep your culture going, while the snails in the main tank will eat algae until they are eaten by your fish.

Which is your favorite freshwater invertebrate for your home aquarium?

  • Snails
  • Shrimps
  • Clams
  • Crayfish
  • Crabs
See results without voting


Freshwater shrimps are quickly becoming a popular choice for home aquariums. They come in a range of sizes and can be entertaining to watch. Many hobbyist enjoy keeping shrimps because of their different colorations. Many species are nocturnal, so chances are high that you will only see them in the morning and at night.

Shrimp tend to not be too picky about what they eat. However, that doesn't mean you can feed them whatever or just have them eat whatever you are feeding your fish. Shrimp, like nearly all animals, need a balanced diet filled with nutrients that they need to grow and live a healthy life. You can get invertebrate food at your local pet store that has been specifically formulated for shrimp. Most species of shrimp will be fine with one feeding each day, and they will be just fine if they miss a day or two of feeding if they are normally well fed.

One thing you need to watch out for with shrimp is the fish you keep them with. That's right there are freshwater fish that will eat your shrimp. Generally a good rule to live by with fish keeping is that if they can fit it into their mouths' then they will eat it, or at least try to.


The most popular 'freshwater' crab for home aquariums is the fiddler crab, sometimes you will see it listed as the mini crab. One thing hobbyist need to keep in mind with these crabs is that they are not completely aquatic nor are they freshwater. This means that they will need some salt in their water and access to the surface of your tank. It also means that they can live out of water. I have heard many stories about these little crabs being master escape artists. Since these little guys are found in marshy areas they are considered to be brackish. Adding a little salt to your tank can greatly improve their quality of life and longevity.

Just like with other freshwater crustaceans you can get food from them at your local pet store. It is possible that these little crabs could eat fish, but only if the fish was small and slow enough and the crab was large and fast enough. Honestly, I consider it very unlikely that they will eat their fishy tank mates.


Often you will see 'blue knight lobster' or 'white ghost lobster', and so on and so forth, in pet stores. These guys are actually crayfish. Crayfish go by many different names depending upon what part of the world you are from, they look like little lobsters. You can get them in blue, red, green, and white.

Most pet stores will tell you that they are peaceful additions to any home aquarium, and they are right they can be non-aggressive. However, if they can catch it they will eat it. That goes for shrimp and fish. Though, if you keep them well fed they should have no reason to go after your fish. Much like feeding shrimp you can buy food for crayfish at your local pet store.

Blue Crayfish

Freshwater Clams


Freshwater clams can be an excellent addition to your non-invertebrate eating tank. They will help clean and the tank water clear. Like all bivalves freshwater clams are filter feeders. They will use the excess food and detritus in the water column as their food source. However, if you fear that this is not enough for your clams you can supplement with invertebrate food from the pet store.

Clams will often bury themselves in whatever substrate you have in your tank. Also, like all invertebrates, freshwater and saltwater, freshwater clams are very sensitive to copper. If you are treating your tank with copper based medication for any reason you need to remove all of your invertebrates. Only once you are sure that you have removed all traces of copper from your tank should you replace your invertebrates.

Freshwater puffers are known invertebrates eaters, often preferring a diet of snails, and gouramis are known to eat snails. Both of which should be avoided if you wish to keep invertebrates.
Freshwater puffers are known invertebrates eaters, often preferring a diet of snails, and gouramis are known to eat snails. Both of which should be avoided if you wish to keep invertebrates.

The Big Picture

Overall the main thing you need to keep in mind before you add freshwater invertebrates to your tank is the tank itself. If you have live plants snails might not be the best option for you. If you have fish that tend to eat invertebrates you will not want to add them to your tank unless you are planning them on using them as feeders. Most freshwater invertebrates are peaceful additions to the home aquarium system.

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dexter 7 months ago

you have fiddler crabs listed as a freshwater crab, but they should be kept in brackish (somewhat salty) water, or they will die within a few months

isharkbait profile image

isharkbait 7 months ago Author

True, fiddlers do need some salt in their tank to be healthy. I keep my tank around 2-3 ppt, and they lived quite well for nearly two years. I have re-read my article and will make the correction. Thank you for pointing out that I had forgotten it!

Gracie 5 months ago

I like this

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