Amphipods: Microcrustacean Biodiversity in Saltwater Aquaria
Amphipods (Gammarus sp.) are an awesome small crustacean to have in both reef and fish-only aquaria! We just started culturing our own amphipods at our aquaculture facility, to hopefully bring this live superfood into your home aquaria!
Amphipods are in the subphylum Crustacea, class Malacostraca, and order Amphipoda. They share many physical characteristics with other crustaceans and may look like mini-shrimps. In the wild, there are thousands of different species of amphipods that live in both freshwater and saltwater. There are even some terrestrial species! Most species are ten millimeters or less; and even though this sounds small, amphipods are actually larger than other planktonic live foods such as copepods.
Adding both amphipods and copepods into the marine aquarium can overall increase the biodiversity of the tank. Amphipods are an excellent food source for marine fish, especially finicky eaters. In the wild, they are an abundant and natural part of marine fish diets. Amphipods are a must for any aquarist who wants to keep seahorses, mandarins, dragonettes, pipefish, and picky angelfish. Amphipods are also very nutritious and will be beneficial to your saltwater fish. They are known to be high in polyunsaturated fatty acids, docosahexaenoic acid (DHA’s), eicosapentaenoic acid (EPA’s), and proteins (Baeza-Rojano, et al., 2014). Marine fish definitely need those extra fats and proteins, as they expend a lot more physiological energy!
Amphipods can also act as part of a clean-up crew in reef aquaria. They are effective detritivores and will feed on waste products, such as leftover uneaten food and fish excrement. This means that it is not entirely necessary to buy separate food for amphipods; whereas, it is recommended to feed phytoplankton to other live foods such as copepods. These little guys will live in the live rock and substrate of the tank while coming out at night to feed. They also like to feed on microalgae, which can help with pesky brown and green films that grow over the sandbed. Amphipods can reach smaller crevices in your rockwork that snails and hermit crabs may not be able to reach!
They may feed on smaller crustaceans as an opportunistic feeder, and can damage copepod populations by consuming egg-carrying females. Amphipods can greatly outcompete copepods, which can decrease microcrustacean biodiversity. A proposed solution to this predicament would be to set up a refugium. Adding a refugium to your aquarium while trying to seed the tank with live food is extremely beneficial. This acts as a refuge and can help increase the density of both amphipod and copepod populations! Offering a place with live macroalgae and live rock or porous biomedia will help amphipods and copepods hide from predators, giving them enough time to reproduce and replenish your live food population!
Amphipods are overall and awesome choice of live food to have in your home saltwater aquarium. Their benefits greatly outweigh the negatives as they are a natural source of proteins and fatty acids for marine fish. They are great for finicky eaters, as mandarins and angels love them! Amphipods also improve the overall cleanliness of the tank by feeding on waste and microalgae. Amphipods really pack a punch in saltwater aquaria!
We have just started culturing amphipods at our aquaculture facility and they are really thriving! We bring back these live superfoods to the store almost every week. If you are looking for some Amphipods or want to try them in your home saltwater aquarium, give us a call and we’ll harvest some for you!
Image of an Amphipod
Image of a Copepod
Works Cited:
Baeza-Rojano, E., Hachero-Cruzado, I., and Guerra-Garcia, J.M. 2014. Nutritional analysis of freshwater and marine amphipods from the Strait of Gibraltar and potential aquaculture applications. Journal of Sea Research. 85: 29-36.