Fish was playing 77/21 with a 3bet of 16.7% over 80 hands, so yeah a maniac. When he doesn't 3bet this hand he honestly could have pretty much any hand bar premiums. Only thing noteworthy is villain had been randomly spazzing out on scare cards on the river, at least 3 times he'd just jammed on the river, but had yet to be called.

Grabbed by Holdem Manager
NL Holdem $0.04(BB) Replayer
SB ($1.21)
BB ($6.15)
Hero ($5.52)
BTN ($6.39)

Dealt to Hero A K

Hero raises to $0.12, fold, SB calls $0.10, BB calls $0.08

FLOP ($0.36) 6 Q 3

SB checks, BB checks, Hero bets $0.30, SB folds, BB calls $0.30

TURN ($0.96) 6 Q 3 3

BB checks, Hero checks

RIVER ($0.96) 6 Q 3 3 A

BB bets $5.73 (AI), Hero ??

Can I profitably call this river, or is it an easy fold? I don't think it's as easy as people think, I think the range he's jamming with is super wide.

Don't cbet the flop. You're playing against two players and a maniac so you're just inflating the pot and inspiring him to bluff. Better to excercise pot control vs maniacs as he's going to bluff when the ace comes anyway and you'll get paid off. Also this QXXss flop isn't the best flop to be cbetting anyway.

The pot odds are horrendous so you have to be 100% sure he's bluffing. In these spots I prefer to just wait for a nut hand and trap him. Like check down trips and let him hang himself.

SB was playing super tight fit fold poker, but I can see why you'd say not to cbet the flop, especially with the maniac. I guess it's whether you have a soul read on an opponent or not ultimately.

if he overjammed river scarecards multiple times before this should be a call
cbet doesnt seem too good to me