Actually, it's not exactly a law on our end rather it's laws in the countries where they originate. These particular caecilians (and all others, for that matter) are illegal to export in all of the countries in which they naturally occur is why it's technically to acquire and keep imported ones under the Lacey Act. The only country that allows for the export of caecilians is Peru, but this particular species hasn't been documented there as far as I know. Sure, they're still imported to the U.S. all the time, but they're purposely mislabeled as "unknown eels" in order to try to dodge the law; these specimens are still illegal to possess as well.