Of the 22 Proteus anguinus offspring, as many as 21 animals have survived, which scientists consider an amazing achievement.

The baby dragons, as they are sometimes lovingly referred to, are growing up in an underground laboratory developed especially for this purpose.

Since Proteus anguinus' larvae are extremely vulnerable and susceptible to various infections, special conditions had to be provided to increase the chances of their survival.

The scientists working for Postojnska Jama are thrilled about the 92% survival rate and the offspring's fast development.

As many as 64 eggs were deposited in 2016 by what is due to its fair complexion often termed "human fish", but the chances of any larva hatching and surviving were minimal.

Statistics show that out of over 100 eggs deposited by a female olm in its lifetime in a natural environment, only two offspring would fully grow up.

While measuring 1.7 centimetres when hatched, the baby dragons are now already 12 centimetres long, so they will soon be transferred to larger aquariums.

"We were worried about how they would accept food, how they would 'socialise'"... A single mistake could result in losing all the 22 precious baby dragons," the company said in a press release on Wednesday.