Product type: Gel food for freshwater fish

Manufacturer: Tetra

Price: Algae Block £6.49 for three 12 gram blocks; Bloodworm, Algae and Brine Shrimp Mixes £6.99 for twenty 4 gram sachets

Pros: Readily taken by a wide range of fish; easy to store and use

Cons: Relatively expensive; rejected by those fish that reject flake 

TetraNatura is a new line of gel foods that includes three different types of gel food for regular meals (Bloodworm Mix with bloodworm and krill; Algae Mix with nori algae; Brine Shrimp Mix with brine shrimp and cyclops), and two feeding blocks for grazers (Algae Block with nori algae; Cyclops Block with cyclops and daphnia). 

Unlike traditional gel foods that are merely jelly with preserved bloodworms or whatever inside them, TetraNatura is a much more nutrient-dense paste-like substance that can be squeezed out of a sachet onto the surface of the water. If squeezed out carefully blobs of TetraNatura food will float for a while, so surface-feeding fish will peck at the stuff. But eventually it sinks down slowly, allowing midwater fish to feed. TetraNatura isn't at all solid, and quickly breaks up into particles, which inevitably means that quite a lot ends up inside the filter. On the other hand, this did mean that very small fish including livebearer fry and Aspidoras catfish found it easier to find morsels of food than they do when flakes or pellets are used. 

Some of my fish went for the TetraNatura foods immediately. These included two different livebearers, Limia nigrofasciata and Ameca splendens, as well as various small catfish and loaches, all of which thoroughly enjoyed the algae-based food. Both my royal plec and my Garra enjoyed the algae block, as did the livebearers. It took a day or two for the Celebes halfbeaks to show much interest in the brine shrimp and bloodworm gels, and a bit longer for the killifish Pachypanchax playfairi, but eventually both species went for them. 

The fish that didn't like the TetraNatura gel foods were those that favour solid, chunky foods, and in this sense this product was a bit disappointing. Those fish that ignore flake foods are likely to ignore TetraNatura gel food too. That my red-tail pufferfish spat out the TetraNatura food isn't altogether unexpected, but more of a surprise was the fact neither glassfish nor my bleeding heart tetras went for the stuff either. 

Tetra market the TetraNatura foods as a complete source of nutrition that can be used as a staple food for tropical fish instead of flake. While that may be true, it has to be said that they're pretty darn expensive for that sort of use, though according to Tetra this reflects the higher costs of producing fish foods of this type. A single 4 gram sachet will adequately feed a 15-20 gallon community tank, which means that a box of twenty sachets is only going to last less than three weeks at a retail price of £6.99, or about ten US dollars. That doesn't compare particularly well with 52 gram pot of TetraMin flake food that costs about half as much but will last at least six times longer! But with that said, because the food portions are sealed in foil pouches, they should retain their nutritional value for much longer than an open pot of flake food, especially in the warm, humid conditions like those near a fish tank! 

As an alternative to flake foods, the TetraNatura line is definitely worth trying out, and is certainly accepted by a wide range of fish. It's a shame that TetraNatura isn't readily taken by fussy feeders like glassfish, but otherwise it's easy to recommend as either a staple or occasional treat for common community fish.