Animal Welfare Act covers dogs, cats, gerbils, hamsters, guinea pigs, non-human primates, and livestock. It does not cover rats, mice, or exotics. Many local laws will have appendixed the federal law to include rats and mice, but still don't include exotics. Birds are fast becomming acknowledges as needing protection, especially those in the pet trade, but fish are way down there on this list, just below reptiles.
Most of the problems lie in the fact that fish are regulated not by Animal Welfare, but by National Marine Fisheries, and state Fish and Wildlife Departments. The regulations refer to fish as, well, a "crop," and are worded for the food-fish industry, not the ornamental trade. Permits are issued that regulate size, that regulate ammount, that regulate fishing seasons, but not everybody applies for the proper permits. There just aren't enough officers to enforce the laws.
The Department of Agriculture is responsible for imports, the US can regulate how much they allow into the boarders, but not how much is caught on the other side. And while they work really hard, it is difficult for them to capture all black-market dealers. As long as there is a demand, the black market will supply.
All State Departments of the Environment have permit requirements for colleciton of anything from the wild. From shells, to leaves, to picking flowers. A permit is required, and is so full of red tape and processing that an individual seining along a private beach to stock their tank is not as much a concern as the individual who is poaching out of season, or who rigs "cat hunts" with retired circus panthers.
Should pet shops be regulated? Undoubtedly. By whom? Departments of Health and Departments of Agriculture are those primarily responsible. Naussa County in NY State has just installed a new branch of their ASPCA that will monitor and enforce animal welfare laws at local pet shops. Unfortunately this only applies to dogs and cats, they are trying to stem the tide of backyard breeders that sell to these type of places. While they can note down injustices against reptiles or aquatics, or issue orders of compliance to clean up their shops, legally, there is nothing they can do. Reptiles and fish just do not fall under animal protection.
If you think that LFS should have their aquatics rooms inspected, that laws and standards need to be in place for fish keeping, that hobbiest should be required to apply (and pay) for lisences of ownership of fish (Pirranha in the state of NY require owners to hold permits if they intend to sell, but requires no permit of ownership), write your local congressperson.
~~Colesea