I edited these pictures from another site that (I will link, to give credit) I changed for my own benefit to see where things were a lot better. And the info I got from a completely different site that helps with knowing what the fishes are where (that I again will link to so they get the credit). This post is more for me to fall back to in case I ever lose the pictures. xD
I hope this info helps others like it did for me
You can use Luminous Dye to make the fish light up still on Orb Vallis like you could on the Plains of Eidolon.
To know if a spot has fish you will need to look for an oily sheen on the surface of the water.
Info to go with this map is here:
Coolant Reservoir Lake, the large lake directly west of Fortuna: (yellow)
Echowinder (common in warm weather)
Kriller (common in warm weather)
Sapcaddy (common in cold/freezing weather)
Longwinder (rare in warm weather, Longwinder Bait)
Landlocked bodies of water (ponds) scattered around Orb Vallis: (red)
Eye-Eye (common in warm weather)
Tink (common in cold/freezing weather)
Brickie (common in warm weather)
Recaster (rare in cold/freezing weather, Narrow-Spectrum Bait)
Tromyzon (rare in cold/freezing weather, Tromyzon Bait)
Info to go with this map is here:
Caves with active bodies of water found in Orb Vallis:
Scrubber (common in cold and warm weather)
Mirewinder (common in cold and warm weather)
Charamote (rare in cold and warm weather, Charamote Bait)
Synathid (rare in cold and warm weather, Synathid Bait)
Fishing Drops
All fish give Scrap, this is a list to what other item you get so that you can find what you need to catch to craft in Orb Vallis
Brickie: Muon Battery
Charamote: Sagan Module
Echowinder: Anoscopic Sensor
Eye-Eye: Rotoblade
Kriller: Thermal Laser
Longwinder: Lathe Coogulant
Mirewinder: Parallel Biode
Recaster: Neural Relay
Sapcaddy: Venedo Case
Scrubber: EXA Brain
Synathid: Ecosynth Analyzer
Tink: Dissipator Coil
Tromyzon: Entroplasma
Pictures came from
Here
Fishing info I found useful to use with the pictures came from
Here