What are those tiny, shrimp-like creatures lurking in the bottom of the fish tank? They are most likely scuds! How did they get there? Are they harmful? And, most importantly, how do you get rid of them?
What Are Scuds?
Scuds are a freshwater amphipod. There are more than 2,000 freshwater species of scuds. They are small, hearty, and reproduce rapidly.
Scuds live in just about any freshwater source, including rivers, streams, lakes, ponds, swamps, and canals. Rocks, roots, and debris provide the scuds with places to shelter and hide. These hungry creatures are omnivorous.
What Do Scuds Look Like?
Scuds may look like tiny shrimp, but they actually have three body segments. They have a head with two pairs of antennae, a thorax with seven pairs of legs, and an abdomen with swimming appendages.
Mature scuds are about half an inch (10-20 mm) long. They can be tan, brown, white, gray, or yellow.
How Do Scuds Get Inside Aquariums?
Scuds are hitchhikers! They can come into your tank and your life on aquatic plants, or used pieces from infested aquariums.
Are Scuds Harmful?
Some aquarium owners view scuds as mostly harmless. While a few scuds won’t cause many problems, a few scuds can quickly turn into a full-blown infestation. That is when the problems start.
Competitors for Food
Scuds are constantly on the hunt! They will eat fish food intended for the rightful inhabitants of your tank.
Scuds are able to reproduce at just three weeks old. The females will lay 20-30 eggs after fertilization. Incubation is only 11 days. The baby scuds hatch hungry and independent. They may only be 1 mm when they hatch, but they will quickly grow into adults capable of reproduction.
Scuds may be small, but they can be annoying! They have the potential to harm fish eggs, young shrimp during the molting phase, and snails. There have been documented cases of scuds eating young fish.
Damage to Plants
Scuds will eat your aquatic plants. They are particularly attracted to soft plant matter. Eventually they can eat through the roots and kill the plant.
How Do I Get Rid of Scuds in My Fish Tank?
Bait and Catch
Place several slices of zucchini on top of a net in the bottom of the tank. After a day or so, the zucchini should be covered with scuds! Carefully remove the net, zucchini, and spuds from the tank. Rinse the vegetables under very hot or cold water, then repeat the process.
- This method requires little effort.
- The rest of the tank will not be disrupted.
- This method takes time and patience.
- You will not be able to catch all the scuds.
- You may catch snails, shrimp, or other animals from your tank.
Freeze Them Out
Scuds cannot survive very low temperatures. Remove all living things from your tank. Dump out most of the water. Place the tank in a freezer, or, if it is cold outside, you may place the tank outdoors. One hour in the cold should be enough to kill any scuds.
Refill the tank with water. Change the filter. Carefully examine all fish and plants for any scuds before you place them back in the tank.
- You will be able to maintain beneficial bacteria in the tank.
- You should be able to remove most of the scuds.
- This method only works for small tanks.
- This is a time-consuming process.
Purchase Scud Eating Fish
Some fish, like Cichlids, Loaches, Bettas, Mollies, and Tetras, will eat scuds.
- You get to acquire new fish!
- Your new fish will have a ready meal.
- Not all of these fish are good additions to your aquarium. They may disrupt or harm some of your current creatures.
- Predatory fish may not be able to eat all of the scuds.
- The fish will only eat scuds that are out in the open. There will still be scuds hiding in the substrate.
Unfortunately, this time-consuming process is the only way to completely get rid of the scuds.
- Move all fish and other creatures to a bare bottom tank. Check them carefully to make sure they do not have any stow away scuds.
- Remove everything from the tank.
- Scrub down all decorations and the tank with hydrogen peroxide.
- Allow all the tank components to dry. If you can place them in the sun for a few days, that is ideal!
- Replace the filter.
- Quarantine all plants and shrimp.
- Replace the substrate with a new one (like this one).
- This will get rid of most, if not all, of the scuds!
- This is an intense, time-consuming process.
- All beneficial bacteria will also be destroyed in the process, and you will essentially have to start your tank over.
Scuds are stubborn! Unfortunately, the best way to get rid of them, is also the most difficult. The best way to get on top of a scud infestation is to deal with it as soon as possible.