In his pursuit of tropical fish, Russell (Rusty) Wessel has swum with crocodiles, and underwater snakes, and dodged the occasional leech, but the thing that scares him the most has no teeth. Pollution is one of the major factors endangering freshwater fish around the world.“I’ll swim with crocodiles,” said Mr Wessel. “People eat them in Mexico, and most of the time they are afraid of you anyway, but I won’t swim in a river or lake that is polluted.”More than 20 percent of the 10,000 known freshwater fish species in the world have become extinct or imperilled in recent decades.Mr Wessel will give a lecture on Saturday for the Bermuda Fry-Angle Aquarium Society in Bermuda. The lecture will be followed by a charity fish auction to raise money for freshwater fish conversation and research projects.His speciality is Central American fishes, and he has collected fish from Belize, Costa Rica and Mexico, and many other places.“These days I mostly take photographs and video,” he said. “Sometimes if there is a fish I do not have and I have the proper breeding permit, I will capture it and take it home.”At home in Kentucky, he maintains 90 fresh water aquariums containing 8,000 gallons of water containing mostly fish types called cichlids and livebearers, which he successfully raises and breeds. His tanks are kept in a 14,000 square ft outbuilding on his property.“Maintaining my tanks is a lot of work,” he said, “but I have it fully automated. The water changes are all done mechanically. I just have to feed the fish and clean the front of the aquarium once a month.”He is an active fundraiser for the Guy Jordan Endowment Fund, set up under the American Cichlid Association (ACA) to grant endowments for cichlid research. His photography and writing have appeared in Aquarium Fish Magazine, Aquarist and Pondkeeper, Buntbarsche Bulletin, and many other publications. Every weekend he jets off around the United States or the world to lecture on freshwater fish. He has been coming to Bermuda for the last twenty years.His interest in fish started when he was a young child. His mother bought a little tank with some fish and asked him to maintain it and feed the fish. He fell in love with the hobby and by the time he was ten years old was keeping ten or 12 tanks. By the time he became a teenager he had about 25 aquariums.“I have always loved nature,” he said.Now his primary interest is conversation as fresh water fish populations are struggling around the world.“Fresh water fish are easier than salt water fish to keep in aquariums,” he said. “Salt water fish do better in the ocean, but freshwater fish do better in captivity. I don’t sell fish. When I give lectures I bring a box of fish along with me and that is donated to the hosting fish group to sell to members. The money raised from that goes to the club or goes to the ACA and the Jordan Endowment Fund.”He has several rare fish in his collection including a species called herichthys labridens. This is a yellow and black cichlid that lives in the desert in Mexico.“In its natural habitat it has practically been wiped out because they introduced an exotic non native fish,” he said. “The herichthys labridens there hybridised with it and are taking over the habitats. The original is slowly being wiped out.”He and several other hobbyists have been maintaining a population of the pure fish for 25 years and could help to reintroduce the fish if the Mexican government got the problem fish under control.This year the Bermuda Fry-Angle Society will be celebrating their 25th anniversary. Mr Wessel will speak at 8pm this Saturday at the Bermuda Aquarium, Museum and Zoo. His talk will be followed by a fish auction. The auction will be opened to non-members for a $10 entry fee or for $20 to become a member.For information e-mail nosteedy@hotmail.com or dmpatterson77@hotmail.com.