So what are scuds in fish tank? A scud is a Gammarus shrimp or close approximation as there are some 1500 species of these tiny tiny Amphipods. There are some 9000 different types of scud think of them as cousins. Another common name you may have come across is water flea! They are often used for food hobbyists use a starter culture or in this case, a scud culture to feed their fish live food.
These scuds also make an excellent clean-up crew as they love algae moss bacteria food waste leaf litter anything rotten they will eat.
These little critters have conquered all waters so it seems. From cold water to tropical hot springs from Antarctica to reefs. From seas oceans rivers lakes springs manmade water holes etc. you get the drift. But they also do well in Aquariums so let’s have a look at all things scud and what they do in our aquariums.
What Scuds Look Like A Description
Scuds are gammarus shrimp-like amphipods from 5-20 mm. They are grey in color but on occasion, they can look tanned orange. Scuds have 2 pairs of antennae and 7 pairs of legs and look like a question mark on their side. Scuds have an exoskeleton made of calcium carbonate which is the same as in our fingernails. They grow for their entire lives and shed this shell exoskeleton and regrow a new one as and when needed.
Aquarium Scuds Life Cycle
There are 100 different scud species that are freshwater scuds. These aquatic insects freshwater scuds once hatched look like adult scuds just smaller. These baby shrimp start off as eggs and are kept on the female scud belly until they hatch this takes between 1-3 weeks.
Freshwater Amphipods Mating Explained
It may be a good idea to back up here and explain how the eggs got there. Well, these small shrimp (scuds) pass their sperm to the female via a brood pouch. Yes, the female carries her eggs in her marsupium the sperm mixes and the eggs hatch revealing juvenile scuds.
Large Numbers Of Scuds
Each female will hatch 50 or so scuds and this will happen every couple of months. The juvenile scuds stay in the pouch for a few more weeks growing and developing until being released into the substrate.
Natural Habitat
Once in the substrate, a small population of these shrimp-like creatures will live in the substrate eating larva bacteria and algae. They love hair algae any live algae and Java moss and any plant matter. They come out at night to get more dissolved oxygen as they breathe via gills.
Fish Fry & Fish Eggs
Although rare our tiny shrimp will eat snail eggs fish eggs and even fish fry. They will spend their life at the bottom of the tank cleaning eating and populating occasionally eating aquatic plants and even fish food. If they run out of food which is unlikely but if they do they will eat live plants so be careful.
Life Cycle End
In our home aquarium it’s actually similar to different species of scuds in the wild These scuds will live for around a year at best. All species of amphipods seem to have a similar timeline.
How Scuds Got Into New Tank
Firstly the easiest way, not the only way is via live plants. That’s right the most common way scuds enter your tank is via live plants you’ve just bought and introduced to your tank. Scuds can easily hide in between the new plants’ leaves. When buying from your local fish store always check the plants and bags they’re placed in.
Scuds In Used Substrate
Another common way is via used substrates. When undertaking a new aquarium setup hobbyists will use a used substrate that has all the beneficial bacteria cycling the new system much faster. This is where scuds live they burry themselves into the substrate. So it’s always best to have a look through the substrate and wash some water over the substrate with a sieve and bucket first.
Scuds Are Hiding In Used Filter Media
Another important thing to check for a scud population is your filter media. As we know similar to substrate hobbyists use some well-used media to help quickly cycle new aquariums. As above it’s always best to give this media a good wash in tank water in a tub or bucket making sure to check for any critters.
Other Ways Scuds Could Enter A Tank
We’ve covered the main ways but it’s entirely possible for any equipment if purchased or being used second hand to carry scuds. So give all second-hand and used equipment a good cleaning before using it in your aquarium This includes lights pumps heaters bubblers etc.
Probably the most conventional way is via buying fish yep they could be in the shop’s water. How many times have you added new fish and got snail eggs a tiny shrimp or some other extra buddy?
Scuds How They Are Around Others
So you now have some understanding of scuds we know what they are a bit about their life cycle and how we can get them in our freshwater aquariums & marine environment without realizing it. We will look at how to keep them as a food source and how to grow a colony of scuds. But first are they dangerous for our tanks Are Red cherry shrimp brine shrimp small fish pond snails seed shrimp in danger of becoming a source of live food for these scuds? Would scuds in a shrimp tank be ok?
Do Scuds Eat Others
So scuds have found their way into your tank. Yes, they are great at keeping a clean tank but what about small live fish? Smaller fish and fry will be eaten if possible Scuds all give it a try if there are enough scuds small shrimp will also be eaten.
Especially if they’ve not developed a shell yet, young fish freshwater shrimp even mosquito larvae pond snail eggs make for great food for our gammarus genus.
Different Experience Blue Scuds & Hyalella Azteca
Even slightly smaller scuds such as the blue scud and the Hyalella Azteca can be problematic. Even the blue velvet shrimp isn’t safe although they normally feed on rotten matter first and much prefer this to anything else. So you could try adding algae wafers if you don’t have enough natural foods.
Let’s look at how you remove scuds from our tanks if they are unwanted before we talk about how we can keep them. Whether in their own scud tank or at the end of the tank you already have.
The Best Way To Remove Scuds From Aquariums
So how to remove scuds from our aquariums? There are a few ways we could introduce a few extra scud-eating fish this works well when the scud colony is fairly small. Keep doing a daily water change to swing the PH and water quality killing the scuds. Good luck as this will take a long time.
Copper overdose the tank with copper sulfate as this will kill scuds problem is it will likely kill all aquatic life so you will need to empty the tank of all life first.
carbonated water more commonly known as the CO2 NUKE. Using water high in CO2 will suffocate the scuds although this method will also kill all life so again you will have to remove them before nuking.
Chemical overdose but yet again the fish and other aquatics will need removing. The same can be said for an algae fix overdose last but not least although time-consuming you could set Scud traps.
Let’s take a closer look at each of these methods of Scud removal. Starting with the only 2 methods that don’t require you to tear down the tank and remove all aquatic life.
Scud Traps
Scud traps or manual removal requires much time. There are 2 common methods the first is to take a nice clean fishnet. Place the net in a nice dark corner without too much of a light source. After finding a good place near the substrate in a dark corner place some nice blanched cucumber zucchini green beans or lettuce on the net. Now wait a few hours and you will have caught plenty of scuds. Simply remove wash rinse and repeat.
Pros & Cons Of Net Method
The pros are its safe cheap and easy and doesn’t kill other life in the tank so no need to remove everything. The cons are its time consuming you can’t guarantee to kill all scuds you may catch other aquatics and have to keep putting them back. You will also have to experiment with which foods to tempt the scuds with.
Vial Trap
A variation of the net is to use a vial some use a simple Planaria Trap. These are normally used for shrimp but work well for trapping all small pests. Place at the bottom as before somewhere nice and dark where the scuds may congregate. Put some small pieces of shrimp inside the trap. You could try veggies as before but the smell of the shrimp will entice them so we wait as above.
Pros & Cons Of The Vial Method
The same as the net method pros are the fact it is safe cheap easy and doesn’t harm any other aquatic life. Cons It’s time time-consuming you can’t catch them all and you will catch other aquatics and have to keep returning them back to the tank.
Scud Eating Fish
Probably the most logical way is to add fish if you don’t already have any that eat scuds. You have a myriad of fish to choose from here are a few Oscars Loaches Betta fish Cichlids mollies tetras and even pea puffers the list goes on but these will all eat scuds happily.
Pros & Cons Of Scud Eating Fish
The pros are it’s quick and easy just add fish. No waiting no prep time It is also efficient and safe and apart from acclimatizing the fish you don’t need to remove other life from the tank. Cons adding fish you may not want or need won’t work on shrimp-only tanks as fish will eat them too. Although these fish will try to eat all scuds some may survive.
Chemical Overdose Excel
This product is used for plant life as it has bioavailable carbon formulated for plants. Hobbyists have realized over time that dosing of 10 times the regular 1 capful or 5ml per 250 liters/ 60 Gallons will kill all scuds.
Algae Fix Overdose
The same results have been seen with Algae fixes This product stops green water and removes phosphates from the water killing algae. Again if overdosed will also kill scuds.
Pros & Cons Of Chemical Overdose
Pros are they work really well one and done no need to repeat. Cons are chemicals can kill other aquatics and even plants so you need to remove everything and quarantine while you overdose your main tank.
Carbonated Water Method
Using sparkling mineral water soda or seltzer water we overdose the tank with CO2 killing all Scuds. Simply lower the water levels in your tank as much as possible and cover the substrate with carbonated water suffocating all scuds.
Pros & Cons Of The Carbonated Water Method
Let’s just say it works the scuds are dead. Cons So is everything in the tank unless you have quarantined everything?
Copper Sulfate Method
First, we lower the water levels as much as possible we then dose the water with copper. Add copper sulfate at the concentration of 2mg per liter of water to accomplish at least 2 parts per million copper. All scuds are dead. After 3 days all scuds are dead now you can refill the water in the tank and the next day do a large water change. Test the copper levels with a copper test kit. Keep doing water changes and testing until the water shows the correct levels.
Pros & Cons Of The Copper Method
Again it works. Cons There are so many but it’s just time-consuming. Takes a long time needs an extra kit needs all aquatics to be removed. You need to keep checking as it’s dangerous for other life and you need to be sure before returning life to the tank.
If you want to be sure the scuds are dead and want to be safe here’s the only way to be sure the nuclear option.
Nuclear Option
The nuclear option removes all aquatic life and plants to quarantine tanks and makes sure these tanks are bare-bottom tanks. As you remove fish shrimp and other life keep checking if you see any scuds. If you see them remove them asap. After removing fish etc. visually look for scuds again in the quarantine tank.
Now we can tear down the tank using a siphon and a bucket to remove water to just above the substrate. Now clean all decorations rocks and driftwood using hydrogen peroxide. Leave in the sun to dry this may take a few days.
Quarantine Plants Replace Filter Media
Now we have our tank down to a bit of water and some substrate before we deal with that we can check our quarantined plants looking for scuds. Change our filter media and throw out the old as scuds can live there too.
Substrate From Infected Tank
Although we could get rid of the substrate and start again this is advised. You could put the substrate via a sieve and pour boiling water killing any leftover scuds. This allows us to reuse the substrate and the benefits of any good bacteria.
Now you know how to get rid of scuds but what about culturing and growing for food or for those that want to keep scuds?
Growing Keeping Scuds
Gammarus sp are from North America but have managed to conquer the whole world. Better known as scuds we’ve spoken about them in full but how do you keep them breed them grow them for food and or keep them?
Culture Containers
These water shrimp side swimmers shrimp antipodes or water fleas SCUDS to us are easy to grow and keep. Any container that holds water and is of at least 5 liters will do. Even a Rain barrel or typical plastic garbage can. First, fill your chosen container with aged water and place a couple of inches of dried mulberry leaves.
Sunlight & Areation
Now placing your container in a sunlit location outside is fine as we need to Aerate the water lightly. Now we have our container some aeration and some sunlight which is needed as these critters breed best at around 20-30C 68-86F. Now put a dozen scuds into the container and leave them to culture. They will feed off the leaves and bacteria algae that will start to grow.
Harvest Scuds
After 4 weeks you will have enough scuds to harvest simply fish out using a small shrimp net and shake over a bucket or small container and you have some fish food. You can now replenish some more dried leaves and an occasional water change will help you keep growing scuds.
They do prefer harder water and you may need to add a teaspoon of egg shells in to help keep them and the scud shells healthy.
What Are Scuds In Fish Tank A Conclusion
Well, you now know everything about scuds from the body segments to the different names. The scientific genus and where they first came from. What are scuds Scuds are a small species that resemble shrimp. They eat rotting matter and live in all kinds of waters and most hobbyists feed them to their fish as they have the perfect nutritional profile.
Here is a wonderful video on Scuds that you will also enjoy
I hope you enjoyed the read and feel free to keep reading more from Tankofish thanks again.
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