Yes He is. You are wrong. I've already refuted your false assertion.
"The name Iēsous (‘Jesus’) is the Greek form of the Hebrew name yēšûa˒, a later form of yehâšûa˒ (‘Joshua’; ‘Yahweh helps/is salvation’), which is formed from the root yš˒ (see Acts 7:45; Heb. 4:8 where Iēsous refers to Joshua, the successor of Moses; and Matt. 1:21, which links the name ‘Jesus’ with his role as ‘Saviour’)."
Source: New dictionary of biblical theology. 2000 (T. D. Alexander & B. S. Rosner, Ed.) (electronic ed.). Downers Grove, IL: InterVarsity Press.
"Beginning with Moses and all the Prophets, He [Jesus] interpreted for them the things concerning Himself in all the Scriptures." (Luke 24:27).
In Acts 1:21 we find the juxtaposition of the absolute form of Lord with the name Jesus (ho kyrios Iēsous), a phenomenon which occurs regularly in the Pauline epistles (cf. also Acts 15:11; 20:35). AND, we also find Old Testament passages referring to Yahweh as Lord now being applied to Jesus (Acts 2:25 using Ps 16:8–11). And, note that in Acts 2:34–35 we have yet another use of Psalm 110:1 referring to Jesus, this time by Peter.
Etc... etc... etc...
The fish became a special symbol for early Christians because the letters of the Greek word IXTHUS formed an acrostic for the initials of several common names for Jesus: Iēsous, Xristos, Theou Hyios, Sōtēr (Jesus, Christ, Son of God, Savior).
Note this was in an age where words were regarded not as merely arbitrary symbols, but as repositories of deeper, secret sense, discernible by the learned, acrostics held special significance and revealed deeper meanings.
One suggested starting point for you would be to read 'Jesus and the Old Testament' which R T France published in 1992.
According to Strong's, Iesous does not translate to "God is salvation". Although clearly there are many references to Christ, He is never "named" in the old teastament.