One of the best ways to keep your aquarium inhabitants happy and healthy is to try creating a tank environment that is as close to the natural environment as possible. One way to do this is to introduce amphipods to your tanks as an additional food source, not only for your fish, but also for your corals!
Coral Feeding Ecology
Although corals do not look like it, they are, in fact, animals and have a mouth and a digestive tract. Being sessile, or immobile, animals, they are largely filter feeders and rely on their tentacles to catch food particles. In addition to their tentacles, they secrete a mucus layer which transports food to their digestive systems.
They obtain nutrients from various sources, such as the small creatures living in the water column, dissolved organic material (DOM) and organic material and bacteria trapped in the sediment.
Did You Know That Corals Eat Amphipods, As Well?
The feeding ecology of corals is very interesting, as they not only have a symbiotic relationship with photosynthetic organisms, called zooxanthellae, which provides them with energy in the form of sugars, but they are also able to obtain nutrients from ingesting small creatures from the water column, such as phytoplankton and amphipods. Amphipods, especially, are a good source of protein, vitamins and omega 3-6 fatty acids. As these nutrients cannot be obtained purely through photosynthesis, which uses light energy to convert carbon dioxide and water to glucose (or sugar), the corals need to obtain them from other sources. Proteins, particularly, are important for growth.
Amphipods are a great food source for your aquarium, as they are cheap and easy to cultivate
What Are Amphipods?
Amphipoda are tiny marine crustaceans that make up a large portion of ocean biomass. Unlike other crustaceans, they lack a carapace (the upper section of the exoskeleton) and are usually laterally compressed. As their name implies, amphi– from the Greek meaning different, and –poda also from the Greek meaning foot, amphipods have two different types of legs. This is in comparison to the taxa Isopoda, which have only one kind of leg.
Amphipods feed primarily on detritus and algae (and not on coral), which make them a useful addition to your tank, as they act as biological control agents which prevent the overgrowth of algae. These amazing creatures are an essential component of the marine food chain and form part of the clean-up crew. They help keep your tank clean and healthy.
Amphipods are generally benthic organisms and reside in the sediment at the bottom of the tank during daylight hours, and then enter the water column at night. If you want to observe your amphipod abundance, try shining a flashlight into the aquarium at night, and you should see them swimming around!
While amphipods can sometimes be introduced unintentionally into your aquariums when introducing living rocks or sediment, cultivating amphipods is a great way to ensure a steady supply of food for your aquarium. It is relatively low maintenance, but does require you to manage a number of parameters carefully, such as the filtration, light, salinity and more.
If you plan on cultivating amphipods, you will need:
1. 5-10 gallon aquarium or container
2. Airstone – to keep the water moving in your tank and to improve the environment by introducing more oxygen to the tank
3. Sufficient light – amphipods require about 12-16 hours of dim lighting per day.
One low maintenance way of maintaining amphipods is to have an in-line refugium system which is connected to your main tank. This provides a safe place for the amphipods to breed while cycling the water that is in the main tank through the refugium. This means that you only need to the monitor the conditions of one system and not two, which is what you will need to do if you have an independent amphipod tank. Independent amphipod tanks require water changes about once a month or after harvesting to prevent harmful ammonia spikes – as long as you are not over feeding your little creatures.
Amphipods do best in aquariums with large surface areas, as this ensures that they have plenty of grazing area. Integrating old bio balls, live rock, old filter pads, coarse sand or crushed coral substrates will help provide a grazing area for your amphipods.
If you have an independent amphipod system, it is important to maintain your amphipod tank at the same salinity as the fish/coral tank into which you plan on introducing them. This will prevent unnecessary stress to the creatures and ensure they remain healthy when moved into the main tank.
The optimum temperature for keeping amphipods is between 72 – 82 degrees Fahrenheit. As amphipods are ectothermic, they become more active at higher temperatures and reproduce faster in these conditions. However, if the temperature is too high, it can be harmful to them and lower their reproductive success and survival rate.
You can feed your amphipods with algal pellets or fish food, such as ground up pellets of fish flakes.
Harvesting amphipods is easy, you can just filter the water through a fine mesh net. If you are using a crushed coral substrate as a growth medium, siphon the substrate as if you were gravel vacuuming your tank bottom, and then use a fine mesh net on the water outflow to catch the critters. They are generally easier to catch at night though, as that is when they leave the sediment.
Feeding Your Corals
To feed your corals, simply place the net with the amphipods in your aquarium tank, and squish the net around a bit to get the critters out. As amphipods typically enter the water column at night, it may be beneficial to try introducing them into the tank at night-time or at around sunset when corals would expect them. Regularly feeding your corals may include benefits, such as polyp extension, puffier body tissue, increased color and growth. Consistency is key to a healthy aquarium. It is important, however, to observe and get to know your tank inhabitants to determine what is best for them.
Amphipods are a great food source for corals, as they are a good source of nutrients, such as protein, but cheap and easy to cultivate.