The baby macaroni penguin at the Tennessee Aquarium apparently is being cared for exceptionally well by its parents and is slightly above average in weight, aquarium officials report.

What began as a tiny, slate-gray ball of fuzzy down one week ago is growing quickly, senior aviculturist Amy Graves said.

"Any baby bird grows fast, and penguin chicks are no exception," she said. "This little baby has almost tripled in size in its first seven days."

Dr. Chris Keller, the aquarium's veterinarian, weighed and examined the macaroni chick for the first time Friday morning.

"This baby weighs 484 grams, which is a little more than one pound," Dr. Keller said. "That's slightly heavier than the bell curve for 1-week-old macaroni penguins, which is just fine."

Even though the little bird appears to be doing fine now, Dr. Keller cautioned there are potential challenges ahead.

"When the chick is about 2 to 3 weeks old, it will become more mobile and start moving around," he said. "Once it starts scampering around, it has some potential to get into trouble. One concern is the fact that the baby is covered in down and does not have its waterproof plumage yet."

For now the baby's legs aren't strong enough for it to venture from the nest.

The chick was born to penguins Paulie and Chaos last week. That was the first birth for the pair and the first hatchling for the aquarium's Penguins' Rock exhibit.

There are four other eggs being cared for in the exhibit, aquarium personnel said.