Picking one of three bags of freeze-dried sardines

Freeze dried sardine bag sizes are 1.5, 3 and 6 ounces, with the same fish in each. Our guidance is to use an opened bag within 30 days, so choose the size your pets will finish in that time. The calculator on the sardine page gives a dog's daily share.

What sizes do freeze-dried sardines come in?

Three: 1.5 ounces, 3 ounces and 6 ounces. The listing offers them as one product with a size choice, so there is one page, one ingredient and one label.

Nothing changes from bag to bag except the amount. Each one holds sardines only, with nothing added. The listing calls them "Small to medium fish." We make no claim that the fish in a larger bag is bigger or smaller than the fish in a smaller one.

Whatever the size, the bag is made in small batches in Malvern, Pennsylvania from imported fish. Since the fish is freeze-dried raw, the sardine heads listing has a line worth following for any of our bags: "This is raw fish, so wash your hands after handling it."

How does the 30 day window help you pick a size?

It gives you a clock. A sealed bag carries a best-by date printed on it, and our guidance puts that date 1 year from production. That bag can wait. An opened bag is a different case, because our guidance is to use it within 30 days of opening.

So the question is which bag your pets will finish inside that window. A bag that gets used up in time was the right size. A bag that is still mostly full when the 30 days are over was a size too big.

We are not going to hand you a figure for how many days each bag lasts. It depends on who is eating from it, and we would rather you do the matching yourself. Take your pet's daily share, hold it up against the amount in each bag, and see which one fits inside the window.

We set the 30 days; it is not printed on the label. The label has its own storage lines. The sardine label says, "No refrigerator needed." and "Press the bag closed after opening and keep it somewhere cool and dry." Our storage guide covers keeping an opened bag.

How do you work out a dog's daily share?

The sardine page has a calculator, and that is the place to begin. The label's energy figure is built into it already. The bag says: "Metabolizable Energy: 3,347 kcal ME/kg (approximately 94.9 kcal/oz)". You do not need to look anything up to run it.

The calculator begins at 10 percent of the day's calories, and its note credits that figure to VCA's treat guidance. The sardine listing's FAQ says much the same: "Hold all treats to about 10 percent of the day's calories." If your veterinarian gives you a different number for your dog, use theirs.

Once you have the share, weigh it. Our guide to weighing fish treats shows how to measure a share on a scale. Then compare that share with the bag you are thinking about.

In a dog's day, sardines are a treat or a topper and never stand in for a complete diet. Leave fresh water down and keep an eye on your dog as it eats.

What if a dog and a cat share the bag?

One bag can serve both. The sardine listing covers adult dogs of all sizes and cats, and for a cat it says to break up or crumble the fish.

The shares stay apart. The dog's comes from the calculator or from your veterinarian. A cat gets small pieces. Ask the cat's veterinarian first, and the share is the veterinarian's call. We give no number for a cat, and the 10 percent setting is for dogs only.

Sharing does not stretch the bag past its dates. The best-by date and the 30 days after opening are the same whether one pet eats from it or two.