Review: Live marine foods from KoralSea

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Ireland's KoralSea has branched out into live phyto- and zooplankton in the form of K-Zoo, K-Phyto and K-Fuzz. Dave Wolfenden tries them out.

K-Zoo

At first glance, you might be thinking you’ve mainly bought water. However, look closely, and you’ll see the bottle is actually populated with numerous copepods. Look even closer, and you’ll see it’s teeming with tiny rotifers. Together, these little beasties make a great addition to the reef aquarium in a sort of zooplankton cocktail. 

The copepods include two species: firstly a harpacticoid (Tigriopus), which is primarily a substrate-hugging benthic ’pod. These will happily graze away at biofilm and detritus on any substrate in the aquarium, acting as a miniature clean-up crew; they’re also superb food for small fish species, notably mandarins. Secondly, Parvocalanus is included, which is a midwater swimmer and great food for fish, as well as SPS corals and various other invertebrates. Copepods are a good source of HUFAs (highly unsaturated fatty acids) and DHA (docosahexaenoic acid), so nutritionally you’re onto a winner with these.

Rotifers are even smaller than copepods, and make an ideal food for some filter feeders as well as larval fish such as clownfish. Not only that, they’re highly efficient at processing detritus and bacteria from the water, so adding them to your reef is a no-brainer.

KoralSea suggests a dosage of 50ml per 100 l at least once a month, but I suspect more might be necessary in practice. To get the most out of K-Zoo, regular additions to the aquarium will keep populations of ’pods and rotifers topped up, and using it in conjunction with phytoplankton (such as KoralSea’s K-Phyto) will help, as this feeds the zooplankton. ’Pods and rotifers will reproduce in the aquarium, especially if a refugium is available, but they may be snaffled quicker than they can breed.

K-Zoo is ideal for seeding a sand bed/macroalgae refugium, but additions directly to the aquarium will also be very beneficial. If adding with the intent of establishing healthy populations rather than as an immediate food source, acclimating the little critters by slowly bringing the temperature and salinity in line with the aquarium is a good idea. As far as shelf life goes, you’ll get a good few weeks out of a refrigerated bottle.

Ease of use:

5/5

Value for money:

5/5

Overall:

5/5

Price: 

250ml RRP £12.00; 30ml 'shot' bottles RRP £2.00.

K-Phyto

K-Phyto contains four species of live phytoplankton with sizes ranging from 5 to 20 microns. This product will be of interest to anyone wishing to directly feed clams and soft corals, and it’s also going to be helpful in potentially boosting zooplankton populations, perhaps in tandem with K-Zoo. 

KoralSea’s method of preparing K-Phyto for storage involves separating the algae from the culture medium (F2/Guillard’s nutrients), with a claimed 99% survival rate. They’re not giving much away on what method is used exactly, presumably for proprietary reasons, which is fair enough. The reasoning for separating the algae out is that F2 actually contains things that we don’t really want to be adding to the reef aquarium, such as phosphate and heavy metals. Dump a batch of regular phyto in its medium into the system, and you’re also adding those nutrients, so this approach offers a ‘cleaner’ culture. The trade-off is that K-Phyto has a shorter shelf-life than some commercially-available phytos, although it will keep for a reasonable while in the fridge (as with all of the products here, ‘best before’ dates are included on each bottle).

The bottle needs a good shake before use, as the algae can settle out in storage, but once agitated, it turns a nice dark green, suggesting a concentrated solution. A dosage rate of 5ml per 100 l daily is suggested, so a 250ml bottle is sufficient for ten days in 500 l aquarium. But you can go crazy with the stuff if you want, as it’s difficult to overdose.

Ease of use:

5/5

Value for money:

5/5

Overall:

5/5

Price:

250ml RRP £12.00; 30ml ‘shot’ bottles RRP £2.00.

K-Fuzz

The niftily-named K-Fuzz is a live temperate macroalga from the genus Acrochaetium, and as such it needs to be kept refrigerated, otherwise it’ll rapidly go off. It also won’t survive in the tropical marine aquarium, so this is strictly for immediate consumption by the fish. The alga takes the form of little filamentous pieces in pink-coloured water which has a strong, pungent 'seaside' aroma. Shake the bottle, and simply add as much as required. It appears a little messy, and the fish take a little getting used to it, but for aquaria containing damsels, tangs, angels, etc., K-Fuzz could make for a good ‘treat’ food. It’s claimed to have vitamins not contained in nori sheets, but I’d have liked some info on its nutritional profile, and perhaps a direct comparison with nori. But variety is the spice of life, so at least using it as a supplementary feed makes sense.

I asked KoralSea where the Acrochaetium is sourced from, and they state that it’s cultured, which means it’s pathogen-free and you can be sure it’s from a controlled environment, and will be of a consistent quality — which is good to know.

Ease of use:

5/5

Value for money:

4/5

Overall:

4/5

Price:

250ml RRP £12.00; 30ml ‘shot’ bottles RRP £2.00. 

More info:

www.koralsea.com

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