Medium Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Confusion; Distraction; Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Airspace Structure; ATC Equipment / Nav Facility / Buildings
LGA was doing Visual Approaches with the charted Visual Approach. I had never done this approach prior. Although this is a Visual Approach; we built the approach into the FMS for situational awareness. We made the turn toward the runway and the controller stated that he got an altitude alert of 900 feet. I immediately disconnected the autopilot and leveled off and went straight to the runway. I was below the VASI but held my altitude until I was back on the VASI for a stabilized approach and landed safely. I was over water and free of obstacles. The biggest issue was attempting this difficult approach at night without knowing exactly what and where my references are. The approach plate has no altitudes to fly except to the starting altitude of 2500 feet. Fatigue and night flight compounded the issue. I suggest ask for the RNAV approach. After landing; I realized other planes were doing the RNAV  approach. Why? I was told they are not authorized. Possibly we should not be also or at least do the approach during daylight before attempting at night.
Pilot reported while conducting a Charted Visual Approach at night they received a low altitude alert from ATC.