I am looking for information on early imports of Pterygoplichthys and Hypostomus for the aquarium hobby - particularly in North America. I have one published date of 1893 for Hypostomus (in Sterba, Freshwater Fishes of the World) and that is all. Any references or first-hand information would be ...

Two species of sailfin catfishes are established in Florida: Pterygoplichthys disjunctivus and P. multiradiatus.
What are the best characters for distinguishing the two ?
Can small specimens (< 50 mm) be identified to species ?
How does biology of the two differ ?

Thanks very much for your ...

I would like to determine when the following species were first imported into the United States: Hypostomus sp., P. anisitsi, P. disjunctivis, P. multiradiatus, P. gibbiceps, P. pardalis. If anyone on list could provide me with references, price lists, etc., it would be greatly appreciated. Thanks.