Thanks for the responses guys, after doing a bit more digging I'm also certain it's an indian shovelnose. Does anyone know what realistic max size is on these guys? Planetcatfish lists it as 71" but that seems a bit high to me. I'd say he was certainly worth what I paid for him, even if he effectively doubled food costs.
Not necessarily aor. The three Sperata spp are hard to tell apart when young. They all have the spot on the adipose too. It could be acilularis or aor. Seenghala is unlikely to enter the trade IIRC. I've never heard of anyone having it anyway. The other two are offered and kept but rather rarely.