There are a variety of electronic discussion lists on various aquarium-related topics. Here are a few of them, which you may subscribe to, or just browse or search the archives here.

Aquatic-Plants

This is a medium for exchange of information about all aspects of growing aquatic plants as a hobby. Postings on both aquarium plants and pond plants are welcome. Topics of discussion include (but are not limited to): individual plant species, aquascaping, substrates, water conditioners and fertilizers, hardware, compatibility of fish and other organisms with aquatic plants, and trades/exchanges between hobbyists.

Live Foods

This list is for information about all aspects of growing live foods for use within that aquarium hobby. Postings on the culture and suitability of various live foods and food preparations are welcome. Topics of discussion include the live food itself, media and foods for raising live food, nutritional value of various live foods and their suitability for aquarium use, potential pitfalls of various live foods, and trades/exchanges between hobbyists.

NFC (list not active)

The List was for people interested in the keeping, breeding, and catching (for aquaria) of various North American native fish, such as Cyprinids, certain Killies, Darters, Sculpins, Sunfish, et cetera. It does not however, include "Hook and Line" type capturing questions. The archive is still online as it contains useful information.