Preflop open is fine with two tight players behind and a fish in the blinds. On the flop you can at most call (turning the hand into a semibluff-raise with a fish in the pot is hazardous).

 It's problematic to be 3-way, since the chance of being up against a dominating flushdraw increases by a lot (more FD combos out there to begin with, and stronger ranges for betting). You're not doing well vs draws with higher flushdraw, or even a naked higher flushdraw (you're 44% vs a naked NFD taken from a 30%!5% preflop flatting range, and you have negative implied odds).

So call or fold. I would use whatever reads I had on my opponents to sway me here. If SB donks a lot when he hits, that would be an argument for floating more against BB when SB checks. A check-raise'y SB and a BB that only leads strong here, then keeps betting, would be arguments for folding more, and so on. Having 1 out to a straight-flush goes in the call column, and is pretty significant. When that happens, we can win a big pot, sitting almost 200 BB deep vs BB's nutflushes.

Moving on to the turn, when BB keeps betting 3-way, you can fold. You only have 4 nut outs versus a presumably strong betting range. Your other improving cards will give you a bluffcatcher with probably some negative implied odds to go along. SB's presence means you're somewhat handcuffed both on the turn and river (can't plan around bluffing or bluffcatching much), so you're forced to play more of a fit-or-fold game when BB leads for the 2nd time.

Keep in mind this important principle: When you have a hand that's mediocre in both directions (weak SD value + weak draw), you don't want to be pinned between two players that collectively have you beaten in both directions. Then you are the guy padding the pot for both of them.