I think you could barely squeak by EV wise with a $14 b/f on the turn but it would be difficult to quanity 3-way with that turn card so c/f (0 EV) isn't terrible. If the TAG raises the turn (which I would only expect him to do with a limited range of value hands KQss, JT, TT, 98s) than its a fold despite whatever the fish does.
QJ+ and spade draws are definitely still in villain's ranges. The TAG's range probably includes stuff like AQss, ATss, KQss, AJ, JTs-87s, TT; he is unlikely to have a set since he'd raise a wet 3-way flop for value/protection and could probably peel a reasonable wide range. The fish could have all manner of hands QJ+, JT-87, 77-JJ, KQ, QT, KT, T8, Q9, J9, etc since his range is going to be pretty wide given the preflop action.
Board: Js 9d 7s Th
Dead:
equity win tie pots won pots tied
Hand 0: 24.519% 22.01% 02.51% 36803 4194.00 { KdKh }
Hand 1: 34.331% 29.86% 04.47% 49925 7476.50 { TT, AsQs, AJs, AsTs, KsQs, JTs, T9s, 98s, 87s, AJo }
Hand 2: 41.150% 36.31% 04.84% 60714 8089.50 { JJ-77, AJs-A9s, KTs+, QTs+, **s+, T8s+, 98s, 87s, AJo-A9o, KTo+, QTo+, **o+, T8o+, 98o, 87o }