Nathan Hill gets excited over two cultures of copepod from ZM Foods, which finicky marine fish will find hard to resist.
An awful lot of people I talk to don’t really 'get' copepods, admits Nathan Hill. The frequent consensus is that copepods are a bit like Daphnia, except smaller and for marine tanks. Alas, that’s firing pretty wide off the mark.
Copepods differ vastly between species in behaviour, life cycle and even nutritional composition. What makes these two offerings from ZM Foods so exciting is that I’m currently looking at two cultures of 'pod with very different uses.
ReefPods Tisbe contain the Tisbe genera of copepod, and specifically Tisbe biminiensis. Tisbe are far from 'marine Daphnia' in their behaviour. In the wild they are found in shallow waters where they live an almost entirely benthic existence, only getting swept up from the substrate when chance currents grab them.
Down there on the base, they guzzle away on detritus and microalgae so quite unlike the suspended, pelagic kinds of copepod. They’re also small things with an adult length of between 0.7 and 1mm. What makes them so great? For a start, they’re the ideal food for those finicky Mandarins or Scooter blennies.
Even better, they’re a natural clean-up crew. So if you’re sat on a sump or refugium, then I’d get a few pouches and empty them straight in there. The Tisbe will not only start quaffing organic waste but they’ll breed like guppies, hurling out a constant stream of young copepods to act as a supplementary food to the main tank. Yes they’re short-lived, lasting maybe 20 days at best, but it only takes the nauplii ten days or so to start producing young of their own.
The other product, a bag full of orange speckles, is a pouch of ReefPods Tangerine. These guys are relatives of Calanus, a copepod I’ve raved and jabbered about many times before. Now I’ve got access to a living equivalent.
Tangerine pods are noticeably larger, with a body size of 2-2.5mm. Unlike the Tisbe they spend their whole time bouncing around in the water column. They might not have detritus-eating benefits, but as a food source it’d be a brave or very obstinate seahorse that could refuse them. Other drifting plankton feeders like Anthias will be equally excited to have these.
The Tangerine pods need feeding in their own right and with a little phyto- and zooplankton introduced to the tank, they should be able to live a complete life cycle — assuming they’re not all eaten in advance. If the young can reach about 12 days of age, then they reach the stage that they can start to reproduce.
Alternatively, either of these copepod types can be cultured in a dedicated chamber (ZM supplies many if you fancy taking the plunge). So if you’re prepared to keep a brood on the go and constantly fed, you shouldn’t need to repeatedly invest in pouches to have an ongoing food supply.
What’s particularly nice about both of these products is that they are actual tropical species, as opposed to the temperate offerings often seen but not long-lived. So at a temperature of 25°C/77°F these little fellows aren’t on borrowed time. At least not until some hungry blenny spots them.
Verdict
Marine copepods are at an exciting time in the hobby, and these two lines are excellent indicators of where we’re at.
Successful cultures can be used to fuel species that are presently difficult to feed and rear — not just well knowns like seahorses or pipefish but also a whole range of filter feeders, possibly corals.
Get stuck in and start a culture, you’ll be surprised at how addictive it gets.
Price: Live 237ml cultures, Tisbe £26.50; and Tangerine pods £28.50. Available from zmsystems.co.uk
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