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Freshwater Invertebrates for Aquariums: Shrimp, Crabs, and More

Alex loves animals and is an experienced licensed veterinary technician with a BS in Biology and an AS in Veterinary Technology.

This is a snail tank used to house snails in an effort to create a self-populating culture.

This is a snail tank used to house snails in an effort to create a self-populating culture.

Freshwater Crustaceans and Other Invertebrates

Chances are pretty high that at some point in time you have considered adding 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.

Be a Smart Customer: Do Your Research

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.

Common Invertebrates for Freshwater Aquariums

Back to the topic of invertebrates. There are five types of invertebrates that are common in freshwater aquariums:

  • Snails
  • Shrimp
  • Crabs
  • Crayfish
  • Clams

There are many different species within each category, each one having a different temperament.

Snails climbing an aquarium accessory.

Snails climbing an aquarium accessory.

Putting Snails in Your Tank

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.

What Do Snails Eat?

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, 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.

Snail Reproduction

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.

Will My Fish Eat My Snails?

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 snail-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 your 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 enough to keep your culture going, while the snails in the main tank will eat algae until they are eaten by your fish.

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.

Are Shrimp a Good Choice for a Home Aquarium?

Freshwater shrimp are quickly becoming a popular choice for home aquariums. They come in a range of sizes and can be entertaining to watch. Many hobbyists 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.

What Do Shrimp Eat?

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.

Will My Fish Eat My Shrimp?

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.

Crabs Can Be a Fun Addition

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.

What Do Crabs Eat?

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.

Crayfish Are Beautiful, but Hungry

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.

What Do Crayfish Eat?

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.

Consider a Freshwater Clam!

Freshwater clams can be an excellent addition to your non-invertebrate eating tank. They will help clean and filter tank water, which helps to keep it clear. Clams will often bury themselves in whatever substrate you have in your tank.

What Do Clams Eat?

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.

Warning: Avoid Copper

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.

Choose the Right Invertebrate for the Right Environment

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 on using them as feeders. Most freshwater invertebrates are peaceful additions to the home aquarium system.

Questions & Answers

Question: If I were to keep my fish well fed on a regular schedule will they still be inclined to go after any invertebrates that I decide to add to my tank?

Answer: In short yes. The sharks at the aquarium I worked at were well fed and on a regular feeding schedule but sometimes they still snacked on their tank mates. Hopefully, keeping them well fed will discourage this but it most likely won't prevent it entirely.

© 2013 isharkbait


CAAD on June 20, 2019:

The vampire crabs are completely freshwater crabs, theyre awesome.

isharkbait (author) from Virginia Beach, VA on July 23, 2017:

@shrimper Thank you for pointing out the grammatical error, it has since been corrected. I do have a little on freshwater crabs in the article. Though it is important to note that the fiddler crabs are technically brackish water animals. They can survive in fresh water, but they will be healthier and live longer in water that has a little salt. If you are looking for a wider selection of crabs for a fish tank I would suggest saltwater or a terrestrial tank. I myself am partial to hermit crabs of all types.

shrimper on July 22, 2017:

Great article, but you didn't write any crab info! And you need to edit some..... "They will help clean and the tank water clear"


Gracie on May 23, 2016:

I like this

isharkbait (author) from Virginia Beach, VA on March 11, 2016:

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!

dexter on March 10, 2016:

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