The Best Aquarium Invertebrates
Updated: Apr 10, 2020
Invertebrates such as shrimp, crayfish, snails and crabs are mega favourites in the aquarium hobby, and it’s easy to see why! There are tons of species and they’re very easy to keep, and also quite a few that do well in smaller tanks. They are fun to watch and some even have a bit of personality and most have excellent benefits for your tank!
So what are the easiest inverts to keep in our aquariums?
Let’s start with Shrimp
There are multiple shrimp species that are very easy to keep in the aquarium. Shrimp are fun to watch and have a low bioload, meaning you can keep big groups. They also come in a wide range of colours and don’t grow too big. They’re also great at keeping your tank free from algae.
Amano shrimp (Caridina multidentata)
Although not suitable for aquariums under 10 gallons (38L), Amano shrimp are a fantastic addition to peaceful tropical community tanks. They are bigger than dwarf shrimp, which means there is less risk of them being eaten by your fish. They also don’t breed as easily, which can definitely be an advantage if you don’t want 600 eggs being laid at once.
Amano shrimp are the best algae-eating shrimp species. Their larger size (2in) makes them better able to defend themselves in community tanks, setting them apart from the Cherry shrimp. This species is great at eating various types of soft algae as well as decaying plant matter and some leftover fish food. Tankmates won’t be bothered and no specific water values are needed.
Cherry shrimp (Neocaridina davidi var. Red)
Cherry shrimp are among the most popular shrimp species, which is not surprising. They are easy to keep, colorful, they breed easily and make a great clean up crew. Any filtered aquarium of 5 gallons (18L) or more is usually enough for a colony to thrive, so no need for a big tank.
These little aquatic rubies are one of the most popular ornamental shrimp species widely available. They’ll grow to around 4cm and they’re pretty hardy if their water conditions are kept stable. A word of warning - they’ll easily breed within the aquarium. But on the flip side of this, Cherry shrimp make a great option for beginning aquarists looking for their first breeding project. Following the process from the female becoming saddled (yellow coloration appearing in the ovaries, indicating she’ll be reproducing soon) to the fry hatching and growing is simply fascinating.
Cherry shrimp are great at eating different types of hair algae and will also eat leftover fish food. They come in a variety of colors (though a bright red is the most common) and make beautiful tank mates if kept with smaller fish that won’t hunt them. If your cherry shrimp share an aquarium with more aggressive fish like gourami, be sure to add plenty of hiding places to prevent them from being eaten. A healthy colony will usually be able to withstand the occasional casualty, but keep in mind that many carnivorous fish species can wipe out your entire group of cherries in no time. Choose tankmates carefully.
Crystal Red shrimp (Caridina cf. cantonensis sp. “Red”)
It’s not difficult to imagine why Crystal Red shrimp are among the most popular dwarf shrimp. Their coloration is stunning and they’re easier to keep than many other of the beautiful varieties of Caridina cf. cantonensis. Although Crystal Reds are not overly fragile, it is still very important that the water is kept clean and the aquarium is cycled.
Lower quality Crystal Reds are usually stronger than high grade ones, as they are less inbred. Keep your Crystal Reds with non-aggressive tankmates (a dedicated shrimp tank would be best) and you may actually see some offspring after a while.
Not into the Crystal Red’s candy cane pattern for some reason? There is also the Crystal Black shrimp, which looks exactly the same but with black and white stripes rather than red and white. This variety is slightly less commonly kept but still not too hard to find.
As a keeper of dwarf crayfish, I can guarantee that these little critters are a fantastic choice if you’re looking for a fun invert with some personality! They are interesting to watch and always up for a fight, even the dwarf varieties.
Dwarf crayfish (Cambarellus genus)
Dwarf crayfish are smaller versions of regular crays. They are appreciated by aquarists because they’re a lot less aggressive than their larger cousins like Procambarus alleni. Unlike this species they can actually be kept with many non-carnivorous tankmates.
The most popular variety is the Cambarellus patzcuarensis “Orange”, bred specifically to be bright orange. Most other dwarf crays like Cambarellus shufeldtii and montezumae don’t have the bright color, but they definitely don’t lack personality. They are always ready to come running towards you with raised pincers whenever you approach the tank.
An 8 gallon (30L) aquarium can house 2-3 dwarf crayfish, but they can also be kept in tropical community tanks as long as they’re not combined with fish that are large enough to damage them. Provide your crays with lots of hiding places to keep them happy. A good option for this are Shrimp Caves.
Electric Blue crayfish (Procambarus alleni)
Although these bright blue crayfish are much bigger and more aggressive than the dwarf variety, which makes housing them a bit more complicated, they are not difficult to keep. As long as the water is clean, they can thrive in a pretty wide range of water values and temperatures. Because they are so big (up to 6 inches) and aggressive, a larger aquarium (at least around 20 gallons/75L) is preferable. If you want to keep them with other fish, be sure to create enough hiding places and remember that they may try to catch and kill weaker and slower ones. The same goes for fellow crayfish.
Setting up a special tank just for one or two of these crays may seem silly to some, but crayfish lovers agree that it’s 100% worth it, as these inverts have great personalities and show interesting behavior.
Many aquarium crabs require a more complicated setup with access to land and, in some cases, brackish water. Don’t let this scare you off! If you’re not sure how to set up and maintain a brackish aquarium, go for the tiny Thai micro crab, which is fully freshwater.
Red claw crab (Perisesarma bidens)
Red claw crabs can be found in most aquarium stores. Contrary to what most fishkeepers assume, they are not fully aquatic and actually need access to land. A rectangular paludarium of at least around 15 gallons (54L) will keep your red claw crabs much happier than a regular aquarium.
The aquatic part should be at a salinity of around 1.005 and a water level of at least 6 inch (~15cm); add a small filter and heater to keep the water clean and warm. Because these crabs are escape artists, close any holes in the lid of the tank and make sure they can’t climb to the top, or you might end up finding one on the floor! Red claw crabs are omnivores and will accept crustacean foods like Hikari Crab Cuisine as well as frozen foods, algae tablets and fresh veggies.
Thai micro crab (Limnopilos naiyanetri)
Although the amount of info available on these freshwater micro crabs is limited, they seem to be similar to dwarf shrimp in requirements. A minimum aquarium size of at least around 5 gallons (18L) seems preferable. Because they are quite vulnerable, it also seems to be a good idea to keep them alone or with peaceful tankmates like shrimp.
Thai micro crabs like to hang out in floating plants, where they use their claws to filter small pieces of food out of the water. All this means that the key to success with these little guys is to keep everything very calm and peaceful.
Were you missing aquarium snails in this article? If we’re talking about aquarium inhabitants that lack spines (also known as invertebrates) we can’t skip molluscs.
There are many species of snails out there that can be kept in the aquarium. Some, like the algae eating black devil snail, are generally appreciated. Others, like the Malaysian trumpet snail, are despised by many aquarists for their fast reproduction and tendency to overrun your aquarium.
Snails can assist in eating algae and leftover foods. Many species like to burrow, keeping your substrate aerated in the process. Above all, many species are surprisingly fun to keep!
Mystery snails, a smaller species of Apple snail, are a very popular snail that can be found at almost any local fish store. These snails are true detritivores and will helpfully eat different types of algae, decaying plant matter, and leftover fish food. They only live for around a year, so commitment isn’t a huge issue and they’re easy to care for. They get on well with others and will just slide around nibbling on what they can find. Mystery snails are one of the larger snail species in this article, but they still only top out at around 2in, making them a sure bet for smaller community tanks as well as larger ones.
Nerite snails are in high-demand within the pet trade, mainly because they come in a variety of colors and patterns and, unlike most other snails, will not breed in the aquarium. This is a job for most owners as anyone who’s researched snails will see that most commonly, when snails reproduce they’ll create hundreds of eggs. Nerites are intense algae grazers, willing to eat almost any type of algae while not harming any live plants within the aquarium. Zebra and tiger nerite snails will grow to around 2.5cm, the rest are slightly smaller and will mainly grow to around 2cm so these little guys won’t take up too much space in your tank.
Malaysian Trumpet Snail
This particular species of snail is practically required for any planted aquarium. These snails are prized for their tendency to scavenge for food underneath aquarium substrate so if you’ve got a habit of feeding a lonely fish that won't always eat all of what you give them, these little guys will dig in to the rest. They are detritivores and will eat plant and protein matter found underneath the substrate while also coming out to eat soft algae.
They grow to be about an inch and only live for around a year. Their drive to look for food underneath the substrate effectively makes them plow the soil, so to speak, aerating it for live plants. The only drawback is that this species of snail will very quickly and rapidly breed within the aquarium if food is abundant.
Thanks for reading! You might also like The Best Algae Eaters for Freshwater Cleanup.
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