All photographs by author
Frozen food is a crucial part of an aquarium fish’s diet and an excellent substitute for live food. In fact, some might argue that it’s even safer, being flash frozen at extremely low temperatures for an extended period. This eliminates the risk of introducing harmful parasites into the water column. Today, I’ll be trying out a product called Calanus, manufactured by Piscine Energetic, a well-known Canadian company in the hobby for their exceptional frozen Mysis shrimp and other high-quality frozen feeds.
Before diving into the actual review, let’s address an important question: “How does one go about reviewing commercially produced frozen food?” Since most reefers don’t have access to a portable laboratory for content analysis, we rely on the manufacturer’s claims and ingredients. We also focus on different aspects of fish food:
What’s in it (visual inspection)
Where it comes from
Size of the food particles
Lastly, we consider how fish and other fauna react to the food and whether it clouds the water when feeding. These criteria will guide my review of PE Calanus, along with some macro shots of the food.
What’s in it / Where does it come from?
PE’s newest frozen food lists a single ingredient – a small crustacean called Calanus finmarchicus. Calanus is a copepod found abundantly in the cold waters of the Atlantic Ocean. PE sources their calanus from the North Sea off the coast of Norway, where it is highly prevalent. Calanus feeds on various forms of phytoplankton, such as diatoms and dinoflagellates. It is highly valued as a fish food due to its rich content of protein, omega-3 fatty acids, and antioxidants.
An interesting fact about Calanus finmarchicus is that it is often studied with regard to climate change. Scientists track Calanus migration patterns to determine shifts in the North Atlantic region’s climate.
What are you getting?
PE Calanus is available in a single sheet containing 35 pre-portioned cubes, weighing a total of 4 oz. (113 grams). While it may not be the most affordable frozen food option, with an average retail price of around $14, its uniqueness justifies the cost. PE also offers a twin pack that includes their Mysis shrimp, giving you 35 cubes of each for around $24.
How does it look?
Calanus finmarchicus is a relatively large copepod species, measuring 2-4 mm in length, similar to a few-days-old brine shrimp. When thawed, it retains a jelly-like structure and boasts a bright red color due to its high carotenoid pigment content. PE advertises it as an excellent choice for both freshwater and saltwater fish, as well as corals and other filter-feeding animals. Take a look at the following photographs for reference:
PE Calanus triggered a great feeding response from fish in both my freshwater and saltwater aquariums. It was quickly consumed upon introduction into the water column and did not cloud the water at all. Here’s a series of photographs capturing feeding time in my tanks:
Calanus is a small-particle food that works perfectly for freshwater and small saltwater fish. I have also observed a positive feeding response from some of my palythosa, zoanthids, and tube anemones (Cerianthus membranaceus). However, it is too large for small polyp stony corals.
Both my freshwater and saltwater fish thoroughly enjoyed PE Calanus! Its bright red color and distinct aroma make it an excellent choice as a transition food for finicky eaters that refuse to consume other frozen treats. If you’re looking to diversify your tank inhabitants’ diet, provide them with omega-3 acids, and don’t mind paying a little more than you would for brine or mysis shrimp, give PE Calanus a try.
To learn more about Ratingperson and their products, visit Ratingperson.