• Graded 2 to 3 mm - small enough for tetras, rasboras, killifish and juvenile fish that cannot manage a whole bloodworm.
• One ingredient - daphnia, with no binders, colours, preservatives or added vitamins in the declaration.
• Hard chitin shell - Ocean Nutrition's stated reason for the product is that the shell provides roughage through the gut.
• Drifts rather than sinks - the buoyant behaviour mimics live prey and triggers a hunting response in mid-water feeders.
• Naturally high in carotene - Ocean Nutrition lists carotene content as supporting natural colour.
• 2.3% protein as fed - a light food by design; useful for adding variety without adding load to a small tank.
• Blister cubes - a single cube is more than enough for most nano and community tanks.

At 2.3% protein and 96% moisture, daphnia carries less nutrition per gram than anything else in Ocean Nutrition's frozen range. That is not a shortcoming - it is what makes it a light, high-bulk food.

Use daphnia to add variety, bulk and small-particle food to a diet. Do not use it to grow fish out or to condition breeders - the protein is not there to do it, and no vitamins or minerals are added.

Full ingredient declaration

Reproduced exactly as Ocean Nutrition publishes it: Daphnia.

That is the entire declaration. There are no added vitamins, minerals, colours, binders or preservatives, and no ethoxyquin, BHA or BHT. Daphnia are small freshwater crustaceans, commonly called water fleas, and the shell is chitin.

Guaranteed analysis

Ocean Nutrition does not publish a crude fibre figure for daphnia, so none is shown here rather than estimated - which is worth noting given that roughage is the product's stated purpose.

These figures are as fed. At 96% moisture the pack is almost entirely water, and a cube of daphnia delivers very little dry matter compared with its apparent volume.

Push out a cube into a small container and let it defrost without water, at room temperature, for at least 10 to 15 minutes.

Feed two to five times a day, offering only what the fish clear within five minutes. Daphnia disperses widely once thawed, so start with less than looks right - a whole cube is too much for most tanks under 100 L.

Straining through a fine net and rinsing before feeding is worth doing here. Daphnia are small enough that a large proportion of a poorly aimed feed simply drifts into the filter.

Return the blister to the freezer straight away and never refreeze a thawed cube.

Suitable for

• Small freshwater community fish - neon and cardinal tetras, rasboras, danios, white clouds and pygmy corydoras
• Killifish, guppies, endlers and other small livebearers
• Juvenile fish that have outgrown baby brine shrimp but cannot take bloodworm
• Bettas, gouramis and other small anabantoids
• Adding variety and bulk to a diet that is otherwise all flake or all bloodworm

Not suitable for

• Growing out or conditioning fish - at 2.3% protein with no added vitamins or minerals, daphnia cannot do that job
• Use as a staple diet, for the same reason
• Large predatory fish, which will not register a 2 to 3 mm organism as food
• Newly hatched fry - daphnia at this grade is still too large; baby brine shrimp or a liquid fry food is the right step
• Marine aquariums - Ocean Nutrition positions daphnia for freshwater fish and their marine formulas are the right fit there
• Treating any digestive complaint - the roughage is a dietary property, not a remedy, and no health claim is made for it

• Frozen Nutris Daphnia 100g - daphnia from Ocean Nutrition's Nutris line, if you want to compare the two formats.
• Frozen Rotifers 100g - a smaller organism again, for fry and fish too small for daphnia.
• Frozen Bloodworm Spirulina Garlic 100g - the next size up in frozen food, for when the fish have grown.
• Ocean Nutrition Formula One Flakes 36g - a fortified dry staple to carry the nutrition daphnia does not.
• Frozen Tropical Mix 100g - a blended freshwater frozen food for the rest of the week.

Aquarium foods carry no manufacturer warranty period. Your rights under the Australian Consumer Law apply in full and sit in addition to anything a manufacturer offers, including the right to a remedy where a product is not of acceptable quality on arrival.

This is a frozen product and must stay frozen until it is fed, so it is handled as a cold-chain item rather than a standard ambient parcel. Frozen stock cannot travel by ordinary parcel post; check the delivery options available for frozen goods at checkout before ordering.

What size are the daphnia?

Ocean Nutrition grades them at 2 to 3 mm. That places them between rotifers and bloodworm in the frozen range, and makes them a workable food for small community fish and juveniles that cannot manage a whole midge larva.

Why is the protein only 2.3%?

Because frozen daphnia is 96% water - the highest moisture content of any food in the range. The figure is measured as fed rather than dry, so it is not comparable with a flake or pellet. Among frozen foods, 2.3% is genuinely low, and that is what makes daphnia a light variety food rather than a growth food.

Is daphnia a treatment for constipation or bloating?

No health claim is made for it here. Ocean Nutrition's own positioning is that the hard chitin shell provides roughage through the gut, which is a description of the food rather than a remedy. A fish with a persistent digestive problem needs its water quality and overall diet reviewed, not a single food substituted in.

Can daphnia be the only food I feed?

No. It is a single unfortified ingredient with no added vitamins or minerals and very little protein, so it belongs alongside a fortified staple rather than in place of one. Two or three feeds a week is a sensible share of the diet.

Will small marine fish eat it?

Many will take it, but Ocean Nutrition positions frozen daphnia as a freshwater food and that is how it is specified here. For a marine tank, the frozen marine blends and rotifers are the intended products.

Do I need to thaw it first?

Yes. Ten to fifteen minutes without water at room temperature lets the cube break up so the individual daphnia disperse and drift. Dropped in frozen, the cube sinks as a lump and most of it reaches the substrate uneaten.