|Scientific Name||Palaemonetes paludosus|
|Minimum Tank Size||10 Gallons|
|Water Parameters||67-85° F, KH 3-10, pH 6.6-8.0|
Grass Shrimp are a mid sized shrimp with clear bodies, not quite as clear as Ghost shrimp. The two are incredibly similar and often sold as the same type of shrimp in local fish stores. As grass shrimp are a bit more expensive and larger you should aim for them over Ghost shrimp if you get the choice. Grass Shrimp are very easy to keep, will breed when kept in stable conditions and are excellent clean up crew members. They can also be fed to larger fish that need occasional live foods, making Grass Shrimp breeding for feeding a common choice.
As a tankmate the Grass Shrimp suffers from a short lifespan. The Grass Shrimp will typically live for one year, rarely reaching two years. To keep them for a long period of time you will need to have them breed and sustain their population. As these shrimp will hunt their own kinds larva it is difficult to over populate the tank with them but easy to keep a handful in the tank.
Unlike colorful inverts or fish there is no visible difference between Grass Shrimp. They will all be mostly transparent with a white hue. This allows them to sit on plants and appear the same color as their surroundings, hence their name Grass Shrimp. As there is no difference in appearence high populations or large sizes are the main two things you want to aim for, especially when using them as a live food.
Things To Look Out For
Grass Shrimp are highly susceptible to copper in the water. Copper is usually added to the water when copper pipes are used in your water supply. This could be anything from the cities water as a whole or just an older home. Either way before purchasing any Grass Shrimp you should test your water for copper.
A cheap and easy way to test for copper is this copper testing kit that comes with easy to use and read strips. If the strips are white or almost white then the water will be safe for the shrimp. If the strips start to turn peach then the water has too much copper and will likely be deadly to the Grass Shrimp. Be sure to run your water as cold as possible, letting it run awhile before using the water for the aquarium. Hot water leeches copper much more than cold water will. If your copper levels are still too high then either use a different water source or run the tank with activated carbon.
One of the main ways this copper gets into the tank is through water pipes made of copper. If your house has copper pipes you can just get water from another source like a near by family members home or even a neighbor.
High levels of nitrites are also dangerous. While this is true for most aquatic life, the Grass Shrimp is more easily harmed by nitrites and will die much quicker than fish or other inverts will. Nitrites come from waste and are removed by beneficial bacteria, which grow in established aquariums. This means Grass Shrimp should only be added to older aquariums or aquariums that will have frequent water changes.
Avoid Powerful Suction such as canister filters or powerheads. The small Grass Shrimp can easily be sucked into these and die, spiking the tanks ammonia and nitrite levels. Either reduce the flow rate by blocking the input/output of the device or use lower strength equipment to ensure the shrimp survive.
When Breeding Grass Shrimp these tips should be strictly followed. Larval and young shrimp are far easier to kill with equipment or bad water parameters.
Grass Shrimp Habitat
The Grass Shrimp is commonly found in North American waters in either freshwater or slightly brackish conditions. They live in heavily planted areas with plenty of hiding spots and algae to feed on. This is the type of setting we should establish for the Grass Shrimp in our aquarium.
The first thing to do is decide which type of water you will be using. Not all plants will survive in brackish settings and most fish will not do well in them either.
Next choose what kind of plants you want in the aquarium. These can be as cheap or expensive as you want. A single plant can be cut and replanted all over the tank, allowing a single $5 plant to cover a 20 gallon breeder. This will take time and effort. Planting multiple larger plants is much easier and allows you to have more diversity in the tank.
Remember the type of plant you choose is what the Grass Shrimp will be walking around on. Moss balls keep the shrimp in the open while long plants like java ferns will let them showcase their color blending bodies.
Large rock formations are also common places Grass Shrimp like to spend their time. Choosing flat rocks creates the biggest area without taking up as much water volume as rounded rocks will. There’s a reason we use boards and not basketballs to build structures.
Breeder tanks are a better choice for shrimp tanks, even if you do not intend on breeding them frequently. They are shorter and longer tanks, giving the shrimp more space to walk around. They do not swim around high levels in the aquarium very often, making tall tanks more suited to fish and shrimp combo tanks.
Use under gravel filtration or sponge filters. These cannot harm the Grass Shrimp and create feeding areas for the shrimp. This happens as the debris in the tank is all pulled to a single spot without going into a machine.
Be sure the surface of the tank is constantly agitated or moving. This aerates the water and keeps it oxygenated. Air stones are the common choice but directing any water flow to hit the surface will also bring oxygen into the tank. This is how saltwater tanks are typically set up without the use of air stones.
Arrange the tank so that there is a lot of surface area. This creates more space for algae to grow and for shrimp to crawl. Additionally these spaces can be hiding spots from fish and encourage breeding. This is especially true for small corner spots that are difficult for fish to enter but easy for shrimp to crawl in.
Do not remove rocks from an established shrimp tank to clean off the algae. The exception to this is if the algae becomes incredibly excessive and becomes slimy. If the rocks look like the have turned color but are not coated in slime that means the rock is covered in algae and bacteria and is now considered a live rock. These are great to have in the aquarium.
Choose gravel as your substrate as it is easy for the shrimp to pick food off of. Sand is better than a bare bottom tank as it will absorb nitrites and nitrates, keeping the tank more stable (gravel also does this). A bare bottom tank is the easiest to maintain but provides no benefit to the aquarium. If you are breeding the shrimp as feeders and are likely to clean out the tank often bare bottom tanks may be the right choice.
If your water is too hard you can add driftwood to the tank. This will slowly lower the pH in the tank and leech out tannins. Tannins will make the tank appear brown tinted, giving the aquarium a more natural/muddy look. Some people like this and some hate it. It does not affect the shrimp and can be removed with water changes. An easy way to picture it is to imagine a tea bag being placed into the aquarium, but much slower.
Using Grass Shrimp As Food
As these shrimp breed rapidly and are fairly large they make excellent feeders for large fish. Larger fish tend to have a mostly meat diet, however when they eat shrimp that have only been fed a herbivore diet they are given a lot of plant based nutrients they would not usually get. These concepts have led to the practice of ‘gut loading’ shrimp with plant nutrients and feeding them to other fish that are difficult to keep healthy.
For the most part we will want to feed feeder shrimp cheap plant foods that are high in nutrition. One of the easiest ways to do this is to buy greens from your local produce section and blanch them. This allows you to buy huge foods, relative to the shrimp at least, and produce high quality meaty foods for next to nothing in costs. Buying high end fish foods is around $10 for 3 ounces of food. $10 in produce can feed shrimp colonies, and therefore fish, for much longer.
Feeding Grass Shrimp
As discussed in using these shrimp to feed other fish, blanched produce is an excellent food source for shrimp. Zucchini is a popular choice and very low cost. When kept with other fish the Grass Shrimp should not need to be fed at all. Instead they will find any food that the fish miss while also eating fish waste and various debris found in the tank. You can then supplement their feeding with very small pieces of food or algae wafers.
Keep in mind that feeding shrimp directly will make them eat less debris in the tank. Try to keep feeding the shrimp to a minimum and use very small or thin slivers of produce when feeding them.
Grass Shrimp Tankmates
Grass Shrimp, along with their similar relatives Ghost Shrimp, have been rumored to occasionally attack fish. This is not true. The Grass Shrimp will not harm any fish in the tank but will hunt larval organisms in the tank. This makes them bad to keep with fish you want to breed.
For the Grass Shrimp safety Avoid Aggressive fish like oscars and chichlids. Large fish, like goldfish, kois and loaches will hunt the Grass Shrimp regularly. Baby shrimp will be eaten by just about anything in the tank, even other shrimp.
Good tankmates for the Ghost Shrimp include:
- Cory Catfish
- Otocinclus Catfish
- Hatchet Fish
- Thin Tetra fish
The main reason people do not like shrimp is the fact that they eat dead creatures. If a fish is dying or dead in the tank the Grass Shrimp will quickly move in and start picking at them. They will not do this to a healthy fish. If a fish is letting itself be eaten by the shrimp then it is as good as dead, even if the shrimp were not there to pick on them. Remove dead creatures as soon as possible.
Breeding Grass Shrimp
Grass Shrimp gender is fairly easy to tell when they are older but impossible to tell before they are ready to mate. Females will develop a yellow or orange saddle on their underbellies, just behind their feet/claws. Males will never have any coloration on them and may be more transparent than females. While females are usually larger, the size variance of the species makes this a bad way to tell gender.
Getting a breeding culture going should not be difficult. By buying five or more shrimp the odds of only getting one gender are incredibly low. As they are so cheap you can often buy ten or more for under $10. when buying them do not be put off if they are sold as feeder shrimp, as there is no difference.
Grass Shrimp will breed in just about any tank. As long as they have stable food and both genders you can expect the female to produce eggs. Once females develop their yellow saddle they will call for males to fertilize the eggs. As the eggs develop they will get larger. At this stage the female is said to be “berried” as they look like they have berries in them. They will usually go into hiding as they are more vulnerable due to their scent and added coloration. Once she does she will release a pheromone, calling the males in the tank to fertilize the eggs.
If you do not think your shrimp are breeding it is likely due to predation of the young. In aquariums with large numbers of shrimp, which will actively hunt larval shrimp, there is almost no chance the young will survive. To ensure baby shrimp survival females should be moved to a separate tank to give birth to their young. Once they have given birth the female can be placed back into their original tank.
If you are not trying to mass produce shrimp as feeders than allowing them to breed in their display tank should never over populate the tank with shrimp. Likewise there should not be so many hunting creatures that the larval shrimp never survive. This allows Grass Shrimp to survive for generations in the display tank without issue.
When using Grass Shrimp to feed fish it is important to not harvest all of the adults at once. Always try to keep a few breeding pairs of varying ages. If only old shrimp are left they may suddenly stop breeding and die of old age. Young shrimp may take too long to produce new shrimp, leading to a shortage of shrimp to use as feeders.