Eradicating Scuds In Freshwater Aquarium

You unintentionally find some strange little white creatures roaming on the substrate when you observe your living tank. Perhaps they are scuds that have become a popular topic in the planted tank world for a long time.

Regardless of their controversy, some people are fascinated by them; on the other hand, they are also considered scuds as a nuisance.

Are you made curious by these guys? If you want to learn more deeply about the pros/cons of keeping them in the aquarium, all the fun facts about the scuds will be discussed on this page.

What Are Scuds?

Scuds (Gammarus spp.), also known as side-swimmers, are a freshwater amphipod crustacean species characterized by a shrimp-like body appearance and a small size.

They belong to the gammaridae family. There are more than 200 described scud species distributed across all regions worldwide, making it one of the most species-rich crustacean genera.

Different species of scuds require specific conditions to live, primarily in terms of tolerance levels and salinity. For example, Gammarus pulex is a purely freshwater scud species, so it can not survive in the marine environment. Another is G. Locusta; they are estuarine species that only live in salinity levels greater than 25 percent. But, it should be noted that they are among the robust members of Malacostraca.

You should know that they also have cousins that live on land, including sowbugs, pill bugs, and rolly-pollies. It is difficult to remember every species of them, and you might often be wrong when determining their species.

Habitat

Scuds can occur in unexpected places, such as underground water streams, hot springs, or even saline water.

The freshwater Gammarus species colonized almost all tropical water ecosystems. These organisms can be found in almost all freshwater streams, including ponds, lakes, artificial canals, swamps, and shallow rivers with slow currents.

They usually spend a lot of time inhabiting the spaces between roots, vegetation, or stones. It aimed to protect itself from predators. Some species also inhabit marine environments, despite the presence of several species that reside in terrestrial environments.

Appearance

Unlike real shrimp, their body is divided into three groups, segmented, and do not have a carapace, but rather a hardened flesh with a thicker texture compared to other shrimps.

The first part is the cephalothorax; it’s the head section where two pairs of antennae are attached. Next is the thorax, or body, which consists of seven segments, each with a pair of legs. The last is the abdomen, which contains six segments; each part of it has appendages to help the organism swim.

Generally, scuds are transparent, but they can change color depending on their diet, as the food enters their body through the digestive tract, which has various shades of green.

Besides, they can also present a brownish tint to camouflage themselves with their environment, thereby preventing predators from hunting them. Females carrying eggs on their bodies often exhibit an orange coloration.

How big can Gammarus get? Actually, they can grow in different sizes depending on their species. An adult scud can reach lengths of 10-20 mm in the aquarium.

However, the majority size is usually around 3-8 mm, with males being slightly larger than females. While their color can be brown, reddish-black, grey, yellow, white, tan, etc.

Diet And Feeding

Scuds accept various diets, including animal and plant materials, as well as green hair algae. So, as an omnivore, they can survive well in the wild.

The freshwater Gammarus species have a significant impact on the environments in which they live. When the leaves fall into the stream’s water, they consume it and turn the leaf litter into delicate organic matter. This activity can increase the rate of decomposition of leaf litter.

Temperature And Water Parameters

According to the information on the site, freshwater amphipods are known to be quite hardy. They can survive the winter season as long as indoor temperatures do not drop below freezing. They prefer relatively warm environments and will not reproduce unless the temperature reaches around 25 degrees Celsius (77°F).

Life Cycle

Newborn scuds have a body length of only 1 mm, yet their physical appearance resembles that of mature ones. After that, they should pass through nine different evolution cycles, molting approximately once every five days.

Their lifespan is regularly about one year, and only a few specimens can survive for two years or more.

For some similar species, a colder living environment can support an increased lifespan; however, it slows down their growth rate in its place. At the same time, warmer conditions will encourage rapid growth and sacrifice lifespan.

Reproduction

Different species have distinct reproductive cycles. For example, Hyalella Azteca is one of the most popular scuds for freshwater aquariums. They can reproduce approximately once a month under optimal environmental conditions, with a single large female capable of producing around 60 eggs. Nonetheless, they mostly carry only 20–30 eggs.

Gammarus fries mostly reach an adult age in about 45 days. They can reproduce throughout the year under warmer temperatures, whereas in colder regions, the mating season typically occurs during the summer.

Mating starts when females are molting. They have an intermoult period of 11 days (10-13 days), and males are about 20 days (8-43 days). Males attach themselves to the above female bodies using their legs before molting. Then, females bring out the males for a couple of days on their backs before they molt. Males help shed the old exoskeleton throughout the molting process.

Once fertilization is complete, males leave the females soon. The incubation period typically lasts about 11 days at a temperature of 20 degrees Celsius (68 degrees Fahrenheit). A change in temperature is vital. It can influence the metabolic system of Gammarus.

Are Scuds Harmful To Fish And Snails In The Planted Aquarium?

They are safe for fish. Instead, fish appear happier when they see the scud’s movement. It may trigger their hunting instinct. Therefore, many fish hobbyists use them as an additional food source for their pets.

But they may bring other problems for fish babies. As documented in some scientific studies, they are opportunistic, can eat or hurt the eggs, and even damage small fries.

In other cases, scuds are not really friendly with snails. In particular conditions, they can attack or try to annoy them by continuously grooming or picking up their mucus. As omnivores, they may also eat snail eggs.

This situation might not occur for snail varieties with a trap door. This feature provides protection to their body inside the shell from any external threats that may bother them.

Are Scuds Harmful To Aquarium Plants?

However, many people think that scuds are suitable for planted tanks, but they are still not safe for the aquatic plants.

Some aquarists suggested that minimizing their appetite by adding vegetables, such as zucchini, lettuce, or cucumbers, is the solution. Unfortunately, it is still not completely accurate.

According to reports from other sites and multiple hobbyists’ experiences, the scuds begin to bite the plants’ parts gradually, even though there was another meal in the aquarium. They prefer to eat the delicate parts of leaves and untouched stems. The softer they are, the higher the possibility that Gammarus will snack on them one day.

Some aquatic plant types are often targeted, such as Java moss, hornwort, dwarf sagittaria, Amazon sword, anacharis, rotala rotundifolia, and Java fern.

From the list above, you can see that even the Amazon sword with a hard texture can still be pulverized when they feel hungry.

Another problem is that they may burrow under the substrate and start eating the roots, weakening the plants and causing them to decay.

It seems that floating and fast-growing plant types have a great chance of thriving in a freshwater aquarium with scuds. Salvinia natans, Azolla cristata, and duckweed are the samples. They can grow faster and more steadily than Gammarus can eat.

Is Scud Bad For Shrimp Tank?

In fact, yes, they are dangerous and should not be kept in the same aquarium, so if you want to achieve a successful goal in breeding shrimp.

We will explain some reasons from the statements before:

• Food Competition: Gammarus are very voracious scavengers. They may easily outcompete shrimp because they share the same resources, including food (such as algae, biofilm, and detritus), living spaces, and substantial ecological overlap. This often results in competition between them, which ultimately hurts the shrimps.
  Furthermore, keep in mind that baby shrimps spend several days hiding in one place with plenty of plants and are not brave enough to swim into open areas to find food. Instead, shrimp fries are just waiting for floating particles, biofilm, or algae to approach their nest.
  Young and adult scuds will explore the tank entirely to discover anything they can eat without concern for their tankmates. So, if your shrimplet numbers are lessened, it indicates outcompeting.
• Tolerance: As we know, they are one of the most successful creatures that can survive well in various freshwater ecosystems. Several species can survive in environments with higher temperatures, lower oxygen levels, increased salinity, pH fluctuations, and even in areas out of the water for several days.
• Potential Aggression: Although we do not have conclusive evidence that scuds strike or eat young or adult shrimp in an aquarium. However, it does not mean that we should disregard the possibility, especially when shrimps are weak and vulnerable during the molting cycle.
• Breeding Competition: Scuds have a shorter reproduction cycle and are faster than shrimp. Their populations will rise rapidly, consuming more food and leaving only a slight food source for shrimp.

How Can Scuds Be Introduced Into Your Fish Or Shrimp Aquarium?

Sometimes Gammarus enters the aquarium accidentally or the keeper’s mistakes. The typical cause is that they often hitchhike on new aquatic plants added. The baby scuds are clever enough to hide within the plants, mainly moss species, which are their favorite food source.

You probably don’t notice because their size is too small to see, but they begin to burrow up into the substrate. After several weeks, the number grows, and the colonies start to appear in your tank.

Another way to invite Gammarus to invade your aquarium is by introducing it from the water in the fish bag or by attaching it to fish bodies or snail shells that you recently purchased from a seller.

How To Get Rid Of Scuds In Your Aquarium?

Removing scud colonies until there are none is almost impossible unless your tank base is empty. So, think again before adding something to your freshwater tank or shrimp aquarium. Below are some techniques that you can try in wiping the Gammarus effort:

Remove Manually

This method may require a significant amount of time and effort; do not expect to clean all scuds in a short period. Some creatures, such as shrimps, fish, or snails, can get trapped in your net; be careful. Here are the steps you should follow:

• Locate a net on the tank floor
• Place a small piece of blanched lettuce, carrot, cucumber, zucchini, cabbage, or green beans in the net. Then, left it for a few hours.
• Afterward, you will notice the scuds gathered the entire food.
• Let’s pick up the net from the tank with the food inside.
• Collect scuds or throw them to your fish or other pets.
• Clean the net and repeat the process until you feel enough.

Scuds Trap Method

The planaria traps typically work to capture them, although they require a considerable amount of time and effort. This stuff runs effectively if the scud colonies are not too much yet. How to use it? It is straightforward; add a tiny bit of shrimp or fish food at the bulb end of the vial. Next, positioning it in the dark areas that scuds prefer.

Keeping Some Scuds Fish Hunter

Many tropical fish types prey on most Gammarus families as one of the primary diet resources in the wild. They would be happier if you offered scuds in aquarium environments as well.

Most loach types (such as zebra botia, clown loach, and macrcantha botia), some cichlid species (like oscar, red devils, and julidochromis), pea puffers, betta, platy, guppy, tetras, SAE, garra rufa, molly, etc., usually will hunt like a flash of lightning when seeing them at first sight.

Unfortunately, this technique has some downsides that may have significant effects. In a specific case, you should introduce new fish into your aquarium that you do not want to be in there. For example, even though betta or pea puffers are small, they are still not secure for a shrimptank.

A bigger tank is susceptible; the scud fish eaters probably can not fully eradicate them. Wherever it can be true, you must pay with a lot of time. Based on some reports we found, even loaches, livebearers, cherry barbs, and corydoras were unable to eliminate them in a 40-gallon tank.

Moreover, only in open spaces can they control the number of scuds. While most colonies settled in many hiding areas, like crowded plants under the rocks, sneaking out between the driftwood, and even occupying the filter media.

CO2 Nuke (Carbonated Water)

Another trick for getting rid of scuds is to use soda water, sparkling mineral water, or seltzer water without harming the plants. This way could bump the PH level high and suffocate them. Follow the steps below:

• Reduce the amount of tank water as much as possible. This treatment will be more effective when the water is less.
• Fill up the carbonated water into your tank. Ensure that the substrate is completely covered with this liquid, particularly where Gammarus used to hide.

The disadvantages of this trick are that:

• Consuming much time
• It can kill other creatures, such as shrimp, snails, and even fish. Ensure that you move all your pets to a separate tank.
• You may find some scuds still alive in your aquarium.

Copper Treatment

Most fish keepers do not need to elaborate further on the dangers of copper, which can be particularly hazardous in shrimp and fish keeping. Especially the crustacean genera, including crabs, crayfish, and dwarf shrimp, are very sensitive to this substance. Below is the series of steps:

• Purchase a copper test kit; this tool can help you.
• Drain out as much water as you can. It can gain a successful chance to remove them.
• Supplement the water with copper sulfate at a minimum of 1.5 to 2 mg/L (5 to 10 ppm).
• Abandon your tank in this condition for 3 days.
• Once the treatment process is complete, refill the aquarium and perform a significant water change to reduce the copper concentration.
• After that, reload the tank with water, then check the copper content level.
• Reassure that the copper level should be gone or at least stay at a maximum level that is tolerated by the pets before adding them back. If you sense the concentration is still high enough, perform another water change.

Although this method sounds powerful, it may also have adverse side effects. Several copper particles should remain in the aquarium, and it can still damage dwarf shrimps if you choose to remove them.

AlgaeFix Overdose Treatment

Some people say the AlgaeFix overdosing can work against them. This solution has a specific note: do not use AlgaeFix with crustaceans, such as shrimp, crab, and freshwater lobster. Well, it is what we want. However, do not form the opinion that overdosing this mixture is safe for snails and fish; remove them.

Seachem Excel Overdose Treatment

Some aquarium keepers recommended injecting Seachem Flourish Excel in heavy doses (about 10-15 times or more).

This solution has an active component called glutaraldehyde. It is a biocide that can cause a chemical burn to material tissues. For your information, this biocide is generally used in the medical sector for sterilizing some instruments.

Be aware of this treatment; this can wipe out all tank populations, such as zebra snails and some plants (like moss, vallisneria, subwassertang, etc.). So, move them all to a separate tank previously.

Remember, they are mighty and intelligent creatures. A few of them may escape by digging into the substrate. Stir it continuously to remove them perfectly.

Hydrogen Peroxide Treatment

Many people believe that this method is effective in combating scud invasion. Most of them opted for this option. Below are the steps:

• Evacuate all tank populations into a quarantine aquarium. Left them in there for a couple of days while waiting for the treatment process.
• Detailly check that no scuds are transferred into the quarantine aquarium.
• To medicate, clean, and rub your aquarium, equipment, driftwood, stones, and other decorations, use hydrogen peroxide.
• Lay it all under the sunlight to dry for several days.
• Replace the filter media or sponge; do not reuse it again.

In theory, the substrate from an infected tank should not be used again. However, if you insist on reusing it, boil the substrate for a while until you are confident that the scuds are dead. You can also pour boiling water directly onto the substrate from a boiler, then stir it constantly to dissolve everything in it.

How To Avoid Scuds Infestation In My Aquarium

The best trick to keep your tank away from them is to prevent trouble before it arises.

A crucial step is to always quarantine everything before adding it to your aquarium. Treat anything, including fish, snails, shrimps, plants, crabs, crayfish, driftwoods, decorations, and more from another source, as infected. That is, they have probably been in contact with some biological object that contains scuds or their eggs.

Practicing an extended quarantine is very useful. If some objects contain these pests, they will present themselves sooner or later. Then, you can take action to deal with them.

Some people advise against overfeeding; it is another way to ward off the Gammarus and detritus worms. Although this is a bad practice, in fact, it does not work to fight with them. Despite reducing the amount of food, these little pests can still find some food inside the tank.

Based on some experiments, some scud specimens known to be alive can survive without food for around ten days inside an aquarium.

How To Raise And Breed Scuds In The Aquarium

This is a bonus chapter and may be helpful for anyone who wants to try cultivating them or breeders looking for other food resources with rich nutrients for their animals, such as dwarf frogs or fish.

As we know, they are hardy creatures that can thrive in various environments. Therefore, raising and breeding them at home should not cost too much. Before reading this guide, it would be better to check the scud products on Amazon.

1. We say there is no minimum requirement for the tank size. However, to help you manage, using a 2.5- to 5-gallon tank is recommended.
2. Gammarus are tiny animals similar to dwarf shrimp, which generate the smallest feces. You don’t need a high-pressure filtration system. A sponge filter with large pores is a suitable gear for scud cultivation. It is low-priced, easy to clean, and maintain. In addition, this filter type also provides multiple perforated surfaces, which scuds can use to graze and live in.
3. Please do not give them too much aeration and current. A little bit of bubbles every one or two seconds is sufficient.
4. There is no rule for the substrate type used. Select the kind of types you want; for example, coarse gravel provides more hiding points, making the scuds happier.
5. Additional driftwood or other hardscape materials have more value; they can provide food for a long time and offer a suitable settlement.
6. Keeping some aquatic plants is necessary. They can become a hiding place or a dietary source when they are hungry. However, never think about putting plants that you want; they are safe.
7. Installing an aquarium LED is unimportant. If you plan to keep some plants or algae for continued growth, adjust the lighting intensity and duration as needed.
8. Water parameters have a pretty significant impact on their development progress. The temperature should be around 20-24 degrees Celsius (68–74°F), with a pH level between 7.0 – 8.0, and the water hardness should be about GH > 10. This is the optimal condition for them to reach optimal growth.
9. Calcium compound is promoted in their shell establishment. Add some cuttlefish bones or crushed coral to a breeding tank to accelerate this progress.
10. Feed them a few times weekly. Never lay too much food; a small portion is more than enough. Overfeeding can pollute the water. They consume a wide range of food types, including shrimp or fish pellets, flakes, algae wafers, and blanched vegetables.
11. Continuously monitor the water parameters using a test kit and perform periodic water changes of approximately 10-20% to maintain optimal conditions. Ensure you only use dechlorinated water to secure your scud colonies. Note: scuds can inhabit well inside green water.