Can eating too much fish causes mercury poisoning?

Unlikely: There is some evidence that certain fish carry an extra load of mercury and that mercury levels too high can be harmful . But the effect is subtle and hard to measure and is considered mostly an issue for your children. Outright poisoning requires a concentrated, heavy exposure which is not likely to be present in fish.

Mecury in fish: Big eye & ahi tuna should be avoided due to high mercury level. Yellow fin & white albacore tuna intake should be limited. Skipjack & canned chunk light tuna have a lower amount of mercury. ***fish with very high potential mercury levels include: shark, swordfish, marlin, king mackerel, big eye & ahi tuna, orange roughy & tilefish.