Do you turn this hand into a bluff?
and if yes what sizing do you choose?

PokerStars - $0.25 NL FAST (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

BTN: 118.08 BB
SB: 236.28 BB
BB: 90.16 BB
UTG: 117.28 BB
Hero (MP): 189.84 BB
CO: 262.24 BB

SB posts SB 0.4 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.4 BB) Hero has 7 8

fold, Hero raises to 2.48 BB, fold, fold, SB calls 2.08 BB, BB calls 1.48 BB

Flop: (7.44 BB, 3 players) 6 Q 6
SB bets 3.56 BB, BB calls 3.56 BB, Hero calls 3.56 BB

Turn: (18.12 BB, 3 players) 7
SB bets 8.68 BB, fold, Hero calls 8.68 BB

River: (35.48 BB, 2 players) 5
SB bets 16.96 BB, Hero raises to 80 BB, fold,

Don't post results

not raising river vs fish, unless i know he cr flop with his nuts

Possibly. I feel like villains line reeks of weakness. 3 roughly 45% pot bets doesn't make too much sense. In theory, you do block a very unlikely straight and 76s, so I feel you have a better bluff to raise the river than you would if villain checked to you and you bet.

Given villain's line, I think this is a fine line. I think in theory, it wouldn't be too bad either. Effectively, your only better bluff hand which would take your line seems to me to be 7c5c, and I'm not sure you would raise that pre. You're not repping a huge value range, and this is one of your best bluffs (if not your best), so I feel it is a mandatory bluff. I feel having blockers to the full houses (and some of the most likely 6x like 86s) is more relevant than having the flush draw blockers.

Agreed with everything pjj said. Ideally we would want to not have spades but think blocking the straight and boats is more good than having spades is bad.

unsure, look spewy line vs bonafide fishy..you're relying on villain to think rationally. id prefer the lower variance approach. villain never has straight and we are basically up against two scenarios, mostly 6x and Qx in value camp and missed fd's + random spazz in his bluffs camp. our hand does block his whiffed draws, id be happier just to pass, you cant rely on villain folding even his Qx without decent info on him.

if villain calls me here with QJo or some junk i cant underestimate the -EV consequences from tilt given ive just spunked pretty much a full buy in vs a drooler.

Some fish have here literally all 2 suited cards, fact he folded to raise doesnt mean you didnt had him beaten, i see tons of half pot 3 streets bluffs, and it's not even that horrible play, you migh have better flush draw or bottom pair and still fold to small donk