Career
He collected a total of three medals, one gold and two silver, at the Universiade (1995 and 1997), and later represented his adopted nation Kyrgyzstan at the 2000 Summer Olympics. On that same year, he helped the Russians capture a bronze medal in the 4×100 m medley relay at the FINA Short Course World Championships in Rio de Janeiro, Brazil. Two years later, at the 1997 Summer Universiade in Messina, Italy, Tkachev earned his second career silver in the sprint breaststroke (1:0277), handing an entire medal haul for Russia with a one–two finish, alongside Stanislav Lopukhov.
At the 2000 Summer Olympics in Sydney, Tkachev transferred his Russian citizenship status to compete for the Kyrgyzstan squad, swimming only in two events.
Earlier in the prelims, he made a surprise packet with a fifteenth-place time of 2:15.63, a Kyrgyzstan record, from a small field of five swimmers in heat two. Three days later, Tkachev teamed up with fellow Russian imports Aleksandr Shilin, Konstantin Ushkov, and Sergey Ashihmin in the 4×100 m medley relay.
Swimming the breaststroke leg in heat one, Tkachev recorded a split of 1:03.69, a slowest in the field, but a diverse Kyrgyzstan team settled for seventh place and nineteenth overall in a final time of 3:46.70.
