ReefPods™ are a new line of live calanoid copepods from AlgaGen which we first wrote on about two weeks ago. These new species of ReefPods copepods include Acartia tonsa, Pseudodiamptomus pelagicus, Parvocalanus crassirostris. and an unidentified species AlgaGen is labeling Tangerine Pods. AlgaGen is also releasing a live microalgae food, PhycoPure™ Copepod Blend to provide a convenient, live phytoplankton option for feeding cultures of these copepods. Follow the break to read our play-by-play on these individual copepods and their potential usefulness for various marine aquarium and captive breeding applications.
Acartia tonsa
Acartia tonsa has floated around hobbyist breeding circles for years and has been implicated as a helpful food source for Yellow Tail Damselfish larvae (via Luis Magnasco) and Spotted Dragonette larvae (courtesy Andrew Rhyne). With a nauplii size of only 65-120 µm (0.065 to 0.12 mm) and an adult size of 1000-1200 µm (1-1.2 mm), A. tonsa is the second smallest commercially available copepod. So far, the biggest hurdle in Acartia tonsa has been a perceived requirement for live T-Iso as the only viable food source. This same potential stumbling block might be applicable for the next three introductions.
Parvocalanus crassirostris
Anyone who has investigated the limited success with Angelfish should already be geeked about the release of Parvocalanus crassirostris, which happens to be a known and proven food for the rearing of Centropyge angelfish. The smallest calanoid copepod being released, with a nauplii size of only 40-100 µm and an adult size ranging from 800-900 µm, this species is truly something special. The uses presented for A. tonsa and P. crassirostris are just the first known applications – with further experimentation who knows what other applications may be discovered.
Pseudodiaptomus pelagicus and the “Tangerine Pod”…
We don’t yet know what Pseudodiamptomus pelagicus (opening image) and the new “Tangerine Pod”, aka. the ReefPods™ Tangerine (pictured directly above), may bring to the table. P. pelagicus is said to be larger than the two proceeding species, reportedly 75-160 µm as a nauplii (marginally larger than A. tonsa) and 1200-1600 µm as an adult. However, it is also purported to be the easiest to maintain in culture. The new “Tangerine” Copepod is the largest of the 4, 100-200 µm as a nauplii and 2000-2500 µm for adults. It’s my thought that the Tangerine and P. pelagicus may come in useful as secondary feeds, especially for larvae that continue to require calanoid copepods beyond the first days of their lives. Diversity of calanoid copepod prey items can only help larval fish survival and quality.
The Implications
To put all this talk of size in perspective, first note that baby fish cannot eat anything that doesn’t fit in their mouth. Ironically, it’s thought that one of the bigger problems with rotifers as a feed stems from their size. The average common L-Strain rotifer may vary from 250-340 µm, much larger than many of the copepod nauplii just listed. The other main issue with rotifers continues to be one of nutrition. While Reed Mariculture’s new RotiGrow system fundamentally changed this issue and drastically improved how nutritious a rotifer can be, we have yet to learn if it’s enough for the most sensitive, smallest, and most challenging marine larvae. Quite simply, it’s unrealistic to assume that the rotifer will do it all, and where rotifers may continue to fail, calanoid copepod nauplii are proving to be a better feed.
I alluded to the culture difficulties that Calanoid copepods seem to present; specifically lower densities and a perceived requirement for live food. As a breeder, I’ve been so fundamentally changed (spoiled) by Reed’s algae concentrates that I never want to culture phytoplankton again, so this presents a conundrum. Do I culture algae, or do I go without these new pods? Until we find easier ways to culture these copepods, I think we have a win-win solution to the problem.
As a fish breeder, most of the fish that might require these copepods are frequent and predictable spawners. For example, my Centropyge argi have been spawning nightly for years now. I can literally try to raise some whenever I want. So rather than culturing these copepods for months and slaving over phytoplankton cultures, waiting for the opportunity to present itself, I can probably get a starter culture whenever I need it, and approach these copepods as “batch culture” projects. That means ordering up the pods I want along with the PhycoPure™ Copepod blend and start a batch culture. When cultures are peaking, I can harvest my eggs and give ’em a go. If I want to walk away from it for a while, I can, because the materials I need can be obtained again from AlgaGen’s retailers. In the end, there is a way for me to benefit from these projects without spending 8 hours a month slaving over touchy T-Iso cultures. Trust me, it’s NOT worth it these days.
Ultimately it is the commercial availability of these starter cultures that is the true breakthrough, but it comes with a caveat. If hobbyists turn around and start culturing these feeds themselves, and in turn start selling them around to hobbyists who want them, we risk losing the source. I have to say, I don’t want to return to the days of having to beg around for something like Acartia tonsa. So logically I have to encourage our readers to “vote with their wallets” and realize that their spending decisions make a difference. Choose wisely.
When it comes to these four new pods, they hold great promise for marine fish breeders. However, we are very much just starting a journey into the unknown. AlgaGen’s main innovation is in reliably producing these copepods for market – these are new raw materials for basement tinkerers to push the boundaries of what can currently be accomplished. Culturing these copepods at home may prove challenging, and doing so in quantities even more so. AlgaGen redesigned their website to provide extensive information to help you make progress, but ultimately, AlgaGen is the first to admit that even they don’t have all the answers – we’re all writing the next chapter in marine fish breeding together.
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