This Fishy Turbo indicator is a oscillator type indicator. I copy-pasted the description from the website: http://www.linnsoft.com/tour/techind/ft.htm

The Fishy Turbo is another name for John Ehler's "Inverse Fisher Transform of RSI" which was detailed in the May 2004 edition of TASC magazine.

Resulting values range between 1.0 and -1.0 with bullish triggers occurring at crossovers of -0.5 and bearish triggers of 0.5.

See the visual action of the Fishy Turbo indicator compared to other indicators: Laguerre indicator and Amplified Williams's Persend Range indicator.

This Fishy Turbo Indicator is originally developed for the FST/FSB by zuijaideai.