we might realize. Some large fish (which probably shouldn't be in the hobby anyway) and some pretty excitable and delicate fish are more easily brought in that way. Without a sedative they would be more likely to hurt themselves or others. Less oxygen is consumed by non-panicking fish, increasing the odds that the shipment will make it. They simply might not be in the hobby otherwise.
In that respect, if those items are used correctly, prices on fish in shipments are lower than they would be. Some wild fish conceivably could be several times what they are price-wise. Prices on farm raised fish would be adjusted up correspondingly.
In public and some private aquaria, fish are anesthetized before an operation.
There evidentially is a lot of tranquilizer use with bait minnows, both in moving them to the dealers and even in the bait buckets! (And later in the lake?)
Using tranqs might tempt shippers to pack yet more fish in the box.
I have even heard of them used to put really sick fish "to sleep." It would be sort of like a lethal injection.
I was really startled by the number of offerings out there. A hastily gathered sample would include:
Jungle's Hypno "Fish Calmer" and bag buddies. The last is widely sold on-line and often used by aquarists in shipping fish or preparing them for auction.
Benzocaine is suggested if used as recommended for anesthesia with recovering salt-water fish (not to be used around reef aquaria with inverts).
Aquatronics makes ProTect.
Trance is sold by the Florida Tropical Fish Farmer's Association store.
http://www.ftffa.com/
TRANQUIL Fish Calmer for bait fish by SureLife and SHAD-KEEPER are sold by fishing stores and farm supply places.
Universities may use MS-222 or Tricaine Methanesulfonate in the labs. Brand names
include Tricane-S and Finquel. A prescription is needed and it is expensive. Yet Pond and Koi suppliers sometimes sell it.
A number of aquarists on other lists have discovered the relatively gentle "Oil of Cloves" sometimes labeled "Eugenol." It can usually be found in most large pharmacies and health food stores in liquid form in small bottles. In one
case a guy found it in a drug store as "Red Cross Toothache Medication."
I found it sobering that in an ad for MS-222 the writer instructed the person applying it to use surgical gloves! Talk about melting in your hands!
Boy! Yet another reason to add aquarium water to the shipping water and then dump all that down the drain. (Now what of water supplies? In Europe they're getting concerned about the effect digested birth control pills in the water supply may be having on fish and men. In one Texas river system the issue is human tranqs in the water supply.)
Watch your LFS. Are they just floating and dumping the fish in the delivery bag in the tank, water and all? Gently ask the person doing that if they realize how effectively they are inoculating that tank with fish diseases from the farm. Ask them if they have just tranquilized the fish. "And what sir, would be an overdose?"
I think there are legitimate uses for fish tranquilizers.
However, thinking of that Chicago importer's observation (In the GuppyLog - Mollies, Salt and Asian Imports) that certain Asian shippers evidentially had imprecisely added salt to the holding vats "by hand fulls to buckets", one can't help but wonder if they have the same chemically ignorant people treating and packing the fish for export.