You have to place on this web site an exect place where your ancestor's town Fridental was located. There were many of them across Russia. Surnames could have changed over time, but in relation to location people might respond faster, also knowing location, they will try to recall their ancestors' names, ask questions and such.
Here are former locations of towns Fridental:
1. Dagestan Autonomous Republic-Freydental ( Freydenfeld, Ostrahovka, Ostrohovka) 500 (1926)
2. Kalmik Autonomous Republic-Fridental, Western Ulus - 49 (1926)
3. Crimea Autonomous Republic-
Fridental, Okrech, Ichkin District ( Feodosia District - 273/223___
Fridental ( Khan Tokus, Kantakuzi) Zuysk District (Simferopol Dstrict) 369/320
4. Volga Germans Autonomous Republic-
Fridental. Gmelinskiy canton( Pallasovskiy canton) - 137/129
Fridental - two villages in Zelmanskiy canton. (old name for district)
Fridental - the outskirts of village, Erenbahskiy canton ( Kamenskiy canton) 66/66

This list shows old soviet names for districts, before 1941, many have changed since, but this information is useful during research.