A Feast for Fishes (Among Others)

For National Aquarium Animal Care staff and volunteers, preparing meals for thousands of animals is part of their daily routine. But it's not just any kind of food they're fixing. An animal's dietary needs differ based on species, life stage, size, metabolism and more. Customizing meals like this takes our Animal Care staff and turns them into part-time nutritionists and chefs as they thaw, chop, mix and plate dozens of dishes. So, who's hungry?

Lighter, Colorful Fare

Dozens of species here are mostly herbivorous—to the point that more than half of the Aquarium's kitchens have restaurant-quality fruits and vegetables in stock. Refrigerators are laden with veggies like carrots, lettuce and zucchini; pantry baskets hold ripening apples, bananas, mangoes, and sweet potatoes. Other shelves look more like those of a pet supply store, stocked with everything from gel powder mixes and pellet food to fiber-filled roughage. It's all part of providing healthy, balanced meals.

Reptiles like turtles dine on mixed meals of pellets, fresh fruit and veggies, too. Staff expertly dice mango and pear and cut wide slices of whole squash and zucchini. With many turtles on exhibit (along with other species that might take a nibble), the team errs on the side of caution and makes slightly larger portions.

Animals with slower metabolisms may get small portions daily or have fasting days in between. For example, Linne's two-toed sloths browse on thin strips of lettuce, zucchini and squash each day, with the occasional treat of sweet potato and corn on the cob. The South American yellow-footed tortoises, on the other hand, receive a salad of coarsely chopped lettuce and timothy hay, garnished with a rotation of more than a dozen types of fruit, three times a week.

Small Bites

Some of the Aquarium's omnivores and carnivores get the extra protein they need from invertebrates, like insects, worms or krill. Breeding and growing these can be time- and space-intensive (if not downright impossible). To have enough on hand, staff order new batches of live insects and worms weekly, and frozen krill less frequently.

Other invertebrates are easier to raise, so staff keep a few cultures going behind the scenes. These select species include fruit flies and pinhead crickets (fed to poison dart frogs and smooth-sided toads) and freshly hatched brine shrimp (a great meal for many jellies).

Fixin' Seafood

During food prep, fruity and earthy scents may waft from some kitchens. A slightly briny aroma drifts from the rest: it's seafood! Fish, squid, clams and crabs are part of many omnivorous and carnivorous diets. And, as an aquarium, it's hardly surprising that seafood is what we feed animals the most.

Preparation time varies daily, depending on the number of exhibits requiring food and how tailored the animals' diets are. Every afternoon, staff move fish from freezers to fridges to thaw. They'll soften whatever doesn't fully thaw overnight with cool running water the following morning. Once everything is sorted, inspected and weighed, teams grab their utensils and set to work cracking, cutting and filleting.

Of all Aquarium animals, the Atlantic bottlenose dolphins eat the most—anywhere from 15 to 20 pounds of food per dolphin per day! Staff gradually thaw and weigh enough smelt, capelin and herring for six daily feedings, divvying up the kinds and amounts of fish each dolphin will get throughout the day.

Dolphin Discovery staff track any food preferences the dolphins show. The dolphins' tastes—especially if they find a fish delectable—help staff decide how a fish should be filleted, and which types make the best reward during a complex training session. Occasionally, trainers will offer new species, like salmon or ladyfish, to add variety. They'll gauge the dolphins' reactions and see if they should add any new fish to future feedings.

Broadcast feeding (scattering food across the water's surface) is great for feeding many species at once. Much like aviculturists prepare fruit, pellet and insect bowls for perching birds, aquarists combine fish pellets, dried algae and krill with chunks of capelin in buckets so reef fish can all find something to nibble on.

Some fish in the larger exhibits dwell at deeper depths and aren't likely to come to the surface during broadcast feeds. Instead, they'll have their food brought to them by way of divers. Staff stuff containers topped with a springy, retractable mesh to keep other fish from eating these meals during the divers' descent.

Broadcast feeding is excellent for feeding many mouths at once, but target training is the team’s preferred method when feeding larger carnivores like blacktip reef sharks. They cut up precise portions of mackerel, mahi mahi and sardines based on the sharks' weights. Come feeding time, they'll ensure each shark is getting enough as it swims by its target and make note of any signs of decreased appetite.

Adding Supplements and Medicines

Despite the food's high quality, the freezing and thawing process can cause it to lose a little nutritional value. To counteract this, staff often add supplements to meals throughout the week. Some come in the form of vitamin tablets, mineral powders or liquids.

Others are gel-like pastes designed for specific diets. Complete with protein, fiber, fat and essential minerals, the pastes are useful for lighter feeding days. They also come in handy if staff ever run into delays when sourcing produce or seafood.

Some animals take medicine with their meals in addition to supplements. Medications are drizzled onto seedballs, disguised in pastes, or hidden inside other food items just before feeding.

It's Time to Tuck In!

Finally, when the last of the cutting boards sink into soapy water and carts are loaded with trays and buckets, it's feeding time!

With everyone munching away, Animal Care crews retreat to the kitchens one last time to wash dishes, wipe countertops, mop floors and reset. They have tomorrow's feast to prepare for.