• A Primer on TDS and the Importance on Acclimating and Quarantining New Shrimp

    Lucky you if you are getting new shrimp! Anything new is always exciting! But we’ve all been bitten by the shrimp bug, and that is great. It doesn’t mean that we should be too hasty about putting our new shrimp in their new tanks though. Shrimp bought at the store or sent via (express) courier service need to be acclimated slowly and carefully to their new environment. The transport is stressful to them even if they are well packed in a styrofoam box and breathing bags.

    Acclimating Shrimp
    (contributed by retardo)

    As keepers of shrimp, fish, and other critters, there are plenty of aspects of an aquarium that we must consider, but the primary consideration should always be water quality. If the quality of water is not good, we risk the health of our animal friends through disease, water toxicity, chemical pollution, etc. We measure water quality by many different components: pH, KH, GH, carbon dioxide (CO2) concentration, oxygen (O2) concentration, TDS, and others. We have already covered pH, KH, GH, and CO2 in a separate article. This article will focus on TDS (total dissolved solids).

    What is TDS?

    Total dissolved solids is a measure of all organic and inorganic substances that are dissolved within a liquid (in our application, this is our tank water) and is expressed in mg/L (or ppm). Simply put, TDS is everything in our water that is not water. TDS refers to the salts, minerals, metals, cations, and ions that can be present in water, including inorganic salts (e.g., calcium, magnesium, potassium, sodium, chlorides, carbonates and bicarbonates, and sulfates) and amounts of organic wastes that we can attribute to fish, shrimp, snails, and other tank inhabitants.

    Sources of TDS


    TDS can originate from multiple sources: natural sources, sewage, run-off (urban or agricultural), industrial waste, chemicals from water treatment facilities, water delivery systems (plumbing), waste from the animals in our aquariums, fertilizers and other additives we may add as part of aquarium upkeep, even rocks or other aquascaping materials, such as driftwood, almond leaves, etc.

    Why is TDS important?

    We often hear or read stories about others losing shrimp and/or other aquatic animals and question why they weren’t able to survive. We can point to disease, the use of chemicals/additives that we do not fully understand (e.g., pH buffers), drastic changes in environment, water quality (which includes TDS), etc. Regardless of whichever of these may be the culprit, providing a stable quality environment is key. TDS is important because we are keeping live animals that depend on our care and ability to provide an optimum environment for them to live, survive and thrive.

    Many fish and shrimp are able to accept a wide range of pH, but are more specific about the GH (general water hardness). Animals that live in water are in balance with their surrounding water and are able to remain in a state of equilibrium with all the various salts and minerals (TDS, parts of which can be measured as KH or GH) within that body of water. More salts and minerals generally means higher GH (hard water, which contains higher TDS) and less means lower GH (soft water --> lower TDS).

    To understand “equilibrium,” we must go back to the basic biology of cells. Cells have cell walls, which are semi-permeable membranes. Some things get through, while others do not. The organs in the cells can pump some things in or out of the cells. Some things pass very freely through the cell walls, and the fish (we will talk in terms of fish, but the basic premise applies to other animals, too) needs to work to maintain the proper balance of minerals, salts and water in their cells. If this balance is upset, it may lead to illness and/or death.

    Water, a requirement for all life, flows through the cell walls. If there are more minerals and salts in the cells than in the surrounding water, water will tend to flow into the cells and become more dilute until the water and mineral contents are about equal on both sides of the membrane. If the reverse is true, (water content > salts and minerals in cells) water will flow out of the cells. The fish in the latter case need to work harder not lose the water.

    The "pH shock" Myth

    We often purchase fish, shrimp, and other aquatic creatures from two primary sources: 1) the LFS (local fish store), where the animals are mostly wild caught and 2) breeders. Regardless of the source, we have been taught by online sources and others that we must do at the very least float the bag, allow some tank water into the transport bag a little at a time over a few hours, and then release the fish.

    The reason is so that the fish can adapt to the new pH, otherwise, the fish suffer “pH shock.” This is a myth. Repeat, pH shock is a myth. While the pH certainly plays a role, it plays a much lesser role than previously thought. It is much more accurate to say the fish suffer “TDS shock.”

    When fish are moved from one environment, which contains a certain level of TDS, to a new environment, the level of TDS will likely not be the same. In some cases, there may be multiple moves and each time the fish must adapt. During transport and subsequent transition, the fish must change their metabolism to match the environment of the new water. It is not hard for fish to move from softer water to harder water, but the opposite usually poses a bigger challenge transitioning from harder to softer water. Too much water attempts to enter fishes’ cells which are not yet adapted to remove the excess water causing additional stress.

    Note that this transition has virtually nothing to do with the pH. It goes to show that keeping KH, GH, and TDS stable is the best way to keep fish (don’t forget, we can apply this to shrimp as well) healthy and happy. The pH of water can change during the day without altering TDS. Those of us that keep planted tanks witness this first hand when we inject carbon dioxide (CO2). Plants consume the carbon in CO2 during photosynthesis and produces oxygen (O2) as a byproduct. CO2 and extra O2 both result in lower pH, yet our fish are unaffected. They swim happily about and display their best colors.

    Going back to the pH issue, we cannot completely disregard that it may cause problems in our tanks. The primary problem is the toxicity of ammonia when our tanks’ pH are on the alkaline side of neutral (>7.0 or basic). In alkaline water, ammonia remains in the form of ammonium (NH4+) which does not cross into fish systems easily. For this reason, we do not rule out pH as a factor in fish deaths; however, the probability of this occurring is a lot less than deaths due to improper acclimation and TDS shock. In a stable, fully cycled tank, ammonia toxicity is generally a non-issue as the denitrifying bacteria should be present in sufficient quantities to process excess ammonia.

    Drip Acclimation

    So why is drip acclimation such an important step after you purchase fish/shrimp?

    Generally speaking, one should always use the drip method to acclimate new invertebrates (and fish, for that matter). The drip method takes at least 1.5 hours, but best for 3 hours or longer depending on how much the original water parameters differ from your local (or tank) water parameters.

    Drip acclimating gives your fish or shrimp the time they need to adjust the balance of salts, minerals, and the like in their bodies with the salts and minerals present in the water in their new homes. If the salt content in their bodies is high (origin is hard water) and they are moving into soft water where TDS is low, just dumping the fish/shrimp in may cause them irreparable harm, stressing their bodies and making them susceptible to disease. Their bodies will not be able to adjust quickly enough (via the natural process of osmosis) and lead to shock. This is less likely to be as a result of pH shock, as we discussed previously, but more like from the inability to adjust to the new TDS level. Osmotic pressure changes are much more severe for aquatic organisms.

    By doing a slow drip acclimation, you change the TDS content of the water gradually and allows the fish/shrimp to slowly adapt. The water flow also need not be constant. It may be a good idea to even stop the flow of water altogether and let the animals sit for awhile and then restart the drip. The technique can be adjusted as you see fit.

    There is the notion of acclimating for the pH, but that could take days. We've also noted that pH values can fluctuate in a matter of hours depending on the amount of CO2, O2, light penetration, etc. from our tanks. It debunks the whole idea of pH being the most important value.

    Attachment 3532


    Quarantining Shrimp
    (contributed by Imke)

    Although most shrimp keepers think it is unnecessary, quarantine is a key to minimize losses. Within a few days or weeks after buying new shrimps and introducing them to existing breeding groups, some keepers moan about having fatal casualties every now and then. Shrimp have to not only acclimate to water parameters but to local bacterial colonies and other tank fauna, too. The bacterial count in tanks differs from 1,000-10,000,000/mL water while tap water should come with 10-100/mL (at temperature 22ºC). The unwanted increase of microbial count leads to pathogen bacteria.

    So preparing the newly arrived shrimp to the bacterial count and composition is the most important intent of quarantine. It also protects old stock from parasites, diseases and fungal infections.

    The following quarantine procedure relies on experiences from Kurt Mack, who has been breeding fish and shrimp for many years as a professional. The assumption is to get the shrimp used to local water parameter and to bacterial fauna step-by-step before introducing them into the target tank. A small tank (12-25 L) is sufficient as quarantine container; it should have no gravel but some hiding places and filtration.

    Day 1
    Introduce the shrimp into the quarantine tank. If the transport water isn’t contaminated by dead shrimp, you should use as much as possible for the first charge of the quarantine tank. Top off with suitable water which has similar parameter as the origin water. Use the drip method for acclimating if you have no suitable water. The parameters of the quarantine tank should match the transport water – whenever possible.

    Days 3-14
    Do water changes (30-50%) with aged tap water (dechlorinate, if necessary) every third day; shrimp gets acclimated to local water parameter.

    Days 15-30
    After the first step of acclimating to water parameter is successfully finished, go on and add water of the target tank to the quarantine tank daily. It should be an amount of 2% of the quarantine tank volume. Do it vice versa and add water from the quarantine tank to the target tank. Like this, every shrimp colony gets used to the unknown bacteria populations from the other.

    Further Reading: AMAZONAS, No. 21, Jan./Feb. 2009, p. 20–29 (German).