Why are my shrimp dying?


Mustafa Ucozler


This is a question that I hear quite a bit from various people, so I decided to provide some pointers about what factors could be responsible for the death of your shrimp. This is the scenario: You either purchase your shrimp from the store or order them online. So far so good. Once the shrimp arrive you put them into their new home. Still everything seems fine. Then, not long after, maybe hours, days or sometimes even weeks later, you find a dead shrimp. Then another, and another one.  You panic. You do not know what to do. This is exactly the time when this article will come in handy. So read on.

In general, shrimp are a lot more sensitive animals than fish.  Minute changes in their environment can mean stress and ultimately death for most shrimp.  Although not exclusive, the following list will discuss the most common reasons why your shrimp might be dying as we speak. Going through this list will also help you prevent any shrimp deaths in the future if you follow my suggestions. The list is in no particular order of importance. Rater, it will help you identify what might be reason for *your* shrimp deaths.


Your shrimp were already stressed/sick when they arrived at your home.

It has been my experience that wild-caught (almost all store-bought shrimp) or farm-bred (e.g. Red Cherry Shrimp) imported animals are extremely weak and in really bad condition upon arrival in the US.  When they arrive in stores imported shrimp have gone through a lot of stress in the hands of  catchers, exporters, shipping company, airline, importers, transshippers/wholesalers and finally the stores. By the time the shrimp arrive in the US, the death rate is immense. Total losses are not uncommon and most shipments have losses from anywhere between 20% to almost 100% upon arrival. Further losses follow in the days after arrival. Generally, only a fraction of the animals originally caught in the wild ever reach the tanks of the hobbyists.  The shrimp that do survive this ordeal are usually the shrimp found in dealers' tanks.  Although alive, many of them will be extremely weak and sensitive.  It will be a challenge to keep these animals alive. 

Suggestion: Whenever possible, only buy from reputable breeders or exchange shrimp with other hobbyists who are breeding shrimp in their tanks.  This way you will know that you will start out with healthy, unstressed animals when establishing your own shrimp population. Beware of people trying to sell imported shrimp as "home-bred."  This way, the wild populations will be preserved and you will end up with top-quality shrimp. Many shrimp species are not even described by science, so it is important that mass demand for imported shrimp does not deplete their wild populations to such a degree that they disappear forever. Even when buying domestically bred animals from breeders, keep in mind that there is absolutely no reason why shrimp should die or get stressed out during shipping. Only buy shrimp from someone who has a clean record shipping shrimp (i.e. all of his shrimp usually arrive alive and in top conditions). If you get milky colored shrimp, chances are they have been through a lot of stress.  Beware of sellers that will say that they include "extras" to make up for shipping deaths. Do not buy from them. Sellers who take for granted that some animals will inadvertently die during shipping will not send you high-quality shrimp. Either their shrimp were not high-quality and healthy to begin with or the fact that they do not package the shrimp properly for shipping weakens the animals and they die in transit or a few days or weeks after arrival.


Your water supply has chloramine as a disinfectant.

Most water supplies in the US seem to have switched to chloramine instead of chlorine to provide disinfection for your tap water.  Chlorine and chloramine are toxic to shrimp and your shrimp will die one by one if introduced into water with chloramine.

Suggestion: Buy Seachem Prime. Whereas it was possible to "age" water by letting it sit for a few days with chlorine, chloramine does not dissipate from the water.  It needs to be bound chemically and converted into harmless substances.  This is done by commercial dechlorinators. If dechlorinators are not used, chloramine will keep accumlating in your tank with every water change. Then if you introduce your newly bought shrimp into such a tank, the shrimp will die one by one within a matter of days. You should make sure that you are using dechlorinators that remove both chlorine and chloramine. If you use a dechlorinator that claims to only remove chlorine and you have chloramine in your water supply, even more poisonous ammonia will be released into your water and your shrimp will die immediately.  Also, some dechlorinators themselves seem to be toxic to shrimp in the recommended doses, as I had to find out the hard way early on.  In my experience Seachem Prime has proven completely non-toxic and most economical for this purpose. Although I have not tested all other products on the market, it is the only product I would certify as "shrimp-safe" at this point. If you have access to this product, get it, if not order it online.


You used the hot water tap to fill your tank

Many people use the hot water tank to regulate the temperature of the tap water when making water changes during the colder months of the year.  Shortly after the water change your shrimp start dying one by one.

Suggestion: *Never* use the hot water tap.  The hot water has increased levels of copper, lead and possibly other heavy metals toxic to shrimp. Due to certain chemicals added to the hot water, the copper pipes corrode more easily and release copper directly into the water. Other chemicals are also added to the boiler which, helped by the temperature of the water, release heavy metals into the water. Whereas fish will be fine (in the short term anyway), shrimp will react adversely immediately.


Your water supply has increased levels of copper and lead

Even when using the cold water tap, your water might have increased levels of copper and lead due to copper and lead components in the piping and faucet.  If you are using well water, heavy metals might already have leeched into your well even before the water reached your pipes. Again, as a result your shrimp die "mysteriously."

Suggestion:  Get a good copper test kit (Aquarium Pharmaceuticals makes a good one) and test your water. If there is no copper in your water, test it for other heavy metals.  Test kits for other heavy metals might be hard to come by and expensive since they are not used often in the aquarium hobby, but not impossible to get.  The best solution is to get a Reverse Osmosis-Dionization filter (RO-DI).  This will take out pretty much everything out of the water. Alternatively, you can use a resin-based product or a Polyfilter to remove the copper and other heavy metals.


You are feeding too much

You feed your shrimp just like you feed your fish..i.e. several times a day a good portion of flake food or pellets. Your shrimp seem happy, run for the food and gobble up everything in time. Suddenly, you notice a dead shrimp. This is usually accompanied by your shrimp losing coloration and lack of appetite. Most of your shrimp just sit there and do not do much of anything. They do not even come running for the food during feeding time. In fact, most shrimp do not come at all. You notice your shrimp dying en masse.

Suggestion:  Feed your shrimp very, very sparingly. When I say sparingly...I really mean it. Only feed them tiny amounts of food once a day and only as much as they can gobble up within a few minutes. Do not ever let a pellet or other food item sit in the shrimp tank for several hours or more. Yes, the shrimp will eat it eventually, but the food is polluting the water in the meantime. This advice is especially important in newly established tanks where additional food is a must as no algae had a chance to grow yet. Once algae are growing and the tank is established shrimp should rarely be fed additionally. This mistake is one of the most common killers of shrimp.


You just had a PH crash or PH spike.

Your shrimp tank has been running for a while and everything is going fine. One day, you notice that your shrimp are sitting around inactively, barely moving and not eating at all. Everything else seems to be fine. You check the PH and it's below 6. Your shrimp start dying. Alternatively, you are trying to increase the PH of your water with baking soda or a commercial PH adjuster, you add the baking soda or PH adjuster to your low PH water. The PH shoots up immediately. Your shrimp get stressed out and begin dying one by one over the next few days and weeks.

Suggestion: If your water is very soft from the tap chances are that your tank will experience a PH crash at one point or another as your tank and filter mature. This is because soft water does not provide much PH buffering capability. To increase buffering capability and prevent crashes it is best to add some crushed coral either directly into the tank or in your filter. Crushed coral will gently increase the buffering capability of the water and also gently and gradually increase the PH of the water depending on how much crushed coral you put into your tank. If you decide to add baking soda or another baking soda based commercial PH adjuster, make sure to add it extremely gradually to the water. This should be done over several days to prevent a lethal PH spike.


You changed too much water at once

You perform a very large water change. You notice dead shrimp in your tank a day or two later.

Suggestion:  Do not change too much of your shrimp tank water at once. There are several reasons for this. The first one is especially important in the winter.  During all the seasons but summer very cold water tends to come out of the tap.  If you change too much water all at once and refill it with the ice-cold tap water, your shrimp will experience a temperature shock and many of them will die over the next few days or weeks. For this reason make sure that you either change very little of the water or, if the chemical composition of your tap water is the same as your tank water *and* you absolutely need to perform a large water change, you can let the water sit for a while and adjust to room temperature before adding it to your tank. If your tank water is chemically different from the tap water, this will not work as well. If you have soft tap water, as I do for example, and add crushed coral to your tank to increase PH buffering capability, your PH, KH and GH will usually be higher than that of your tap water.  Hence, if you perform a large water change, the shrimp will experience a shock due to the different chemical composition of the new water. Therefore, it is generally best to only change very little water (15-20%) on a weekly or bi-monthly basis.


You bought a new plant

You buy a new plant, put it into your tank. Within a few hours (or sometimes days) your shrimp are all dead.

Suggestion: Always thoroughly rinse any newly bought plants. Many aquarium plants are grown emerse in plant farms and treated with all kinds of pesticides which are, obviously, extremely toxic to shrimp.  Fish will do fine, whereas shrimp will almost immediately fall over and die. Unfortunately, rinsing does not always get rid of all traces of pesticides. Therefore, it is imperative to buy non-pesticide treated plants or exchange plants with other hobbyists instead of buying plants grown in huge plant farms and offered at your local pet store or your favorite internet retailer.


You medicated your fish

This is an all too common scenario. You have a mixed fish and shrimp tank. Your fish have ick. You treat them with your favorite ick medication. The fish recover, but your shrimp die en masse.

Suggestion: Always check the label of any fish medication you are using. If the label indicates that copper is an ingredient, do not use the product as copper, even in small amounts, is toxic to invertebrates. Other non-copper medication can be harmful to shrimp, too, but very little research is available in this area and hobbyists will need to experiment and exchange experiences concerning the harmfulness of commonly used fish medications for shrimp.


I hope that this article has helped you identify why *your* shrimp are dying.  Keep in mind that a combination of factors might be responsible for any given shrimp death and you should follow as many of the above suggestions as possible. Also keep in mind that adverse factors have a cumulative effect on shrimp. The shrimp will deteriorate more and more over time as it is exposed to additional adverse factors. Most deterioration does not seem to be reversible. Once a given shrimp has been exposed to a certain amount of stress, it just dies.  I will expand this article as more reasons for shrimp deaths come to my mind or are discussed in my forum.  Stay tuned!


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